[a4anurag]

Sometime in the month of March, during a normal city drive, the car started to violently jerk in 2nd or 3rd gear as if I cycled the engine start/stop button - On & Off while the engine was running (under load). The instrument cluster didn't throw any CEL plus the fuel gauge was displaying around the 3/4th mark. Panicked, I switched off the car and decided to wait for a while. Parked the car by the road for ~5 minutes and then started the car to proceeded to meet BHPian interc00led. In half a kilometer, the jerking issue returned and lasted for a considerate distance that helped me record a video of the same. Clueless what was happening with the car as even the ‘ELM 327 + Torque PRO’ didn’t show anything abnormal, different thoughts like fuel filter related or engine/transmission mounting related issue could be the cause for these violent jerks. If someone was in the passenger seat or watching the car from outside, it could give an impression that the driver was a newbie and didn’t know how to release the clutch smoothly. At one point of time, I was genuinely worried if the engine/gearbox would come off it's mounting due to the jerks that it was experiencing. After I reached BHPian interc00led’s house, when he tried to drive the car, all was normal. We plugged-in the Launch x431 PRO diagnostic tool for advanced diagnostics but during that drive; the car behaved normally. Puzzled, we left it at that thinking it was a one-off incident.

Odometer Reading: 74,758 kms;
Date of First Issue: 08.03.2020.

Hyundai Creta - Neutral Switch Issue (violent shaking of the car)

Days passed by and the violent jerking issue started to reoccur like 3 times every time the car was used but no specific pattern could be traced. It had its own mind – the car becomes literally un-drivable during the jerks and no amount of stopping or switching off the engine would solve the issue.

During a normal start from a traffic signal, I upshift to 2nd gear when the engine speed reaches 2,000 RPM (~20kmph) and to upshift when I press the clutch pedal, it is at this moment, the car jerks with harsh clutch disengagement as if I am forcibly disengaging it under load – the engine and gearbox witness a jolt (rocking motion – forward/backward motion). Even the gear lever, gets a ‘tug’ as the engine is jerking making the gearshift vague and loose (not sure if that’s the word to be used). Since this was related to clutch release system, we decide to bleed it once. Headed to our FNG with 2 bottles of 'TVS-Girling' DOT-4 brake fluid to rule out the presence of air in the lines. As a precautionary measure we opened the boot of the slave cylinder and we find brake fluid in there (got accumulated in that boot). Thought this could be the culprit that may be causing the issue since the clutch was not engaging or disengaging as it should. Went to MOBIS and enquired for the part – slave cylinder.

Part Name: Cylinder Assy – Clutch release
Part Number: 41710-23035
Price: ₹3,358.00

The part was not available and would need to be ordered through MOBIS which could take 7-10 days for arrival. I drove the car for 10 days thinking it may go off by itself but no, was persistent. Since the order was under the ‘processing’ stage on Boodmo, we decided to check the local parts area if we could get it faster than Boodmo. Searched a couple of stores and all we got was local parts (aftermarket Korean import) costing ₹1,000.00. Decided to take the risk, we purchased it and headed straight to the garage (cancelled the order on Boodmo). After replacement of the slave cylinder, it took almost an hour in total to bleed the system first via gravity method and then through the vacuum bleeder to be sure that there’s no air in the system. Post replacement, first drive out of the garage and the jerk is violent and very much there (clutch pedal feel, brake fluid levels – all normal). Both of us were blank as we couldn’t relate to anything else and neither of us had any experience with such jerks in any of our previous cars – completely new experience. Disappointed, both of us left for our houses.

Neither of us could comprehend what the issue was, to seek further help, I pinged DBHPian SS-Traveller Sir since I find him highly experienced and he could help us out - I shared the video and the problem with him. Immediately he suggested I clean the accelerator pedal unit and its connections, change the fuel filter and clean the fuel tank too (if required). Since the car was serviced at 70,000 kms by changing all the filters (including the fuel filter), we just cleaned the accelerator pedal unit. That didn’t help either as the jerks were there from the moment go. Helpless, I continued to use the car.

Other than the violent jerking issue, humming issue that is mentioned in the earlier part of my ownership thread (Post #346) was also adding to the misery. Researching about the humming issue online on various Hyundai forums, they were pointing towards a clutch set change that will help solve it. I decided not to get the OEM clutch set (Valeo) and look for alternatives. Since the related issues were with clutch engagement/disengagement, we decided to change the clutch plate & pressure plate along with the release bearing (odometer was 78,705 kms).

Brand Name: LuK
Part Name: Clutch Set – Clutch plate + Pressure plate
Part Number: 62440-16090
Price: ₹5,300.00

Part Name: Bearing – Clutch Release
Part Number: 41421-32000
Price: ₹1,220.00

After 8 hours of work when we drove the car out of the garage, both of us were mighty disappointed again as the jerking issue was present and even stronger this time. Dejected to the core - paid the labour charges for the job and left for home. Only positive in this episode was, the humming issue was completely gone and the car felt eager to move (new clutch, I know!). My FNG owner was feeling that the issue was related to the flywheel and not the clutch set. He advised I get the same replaced at the earliest. Mentally both of us were not convinced that the flywheel could go bust in just 78,900 kms since the car has never been abused from Day 1. For the heck of it, I check the part cost on Boodmo:

Part Name: Flywheel Assy
Part Number: 23200-2A701
Price: ₹12,742.00

Part Name: Bolt, Flywheel
Part Number: 23231-2A000
Price: ₹65 x 8no's = ₹520.00

Enquired at two MOBIS outlets for the flywheel and the bolts, none of them had it in stock and would require a minimum of 10 days to get it from MOBIS Chennai. My worry was – “what if the flywheel to doesn’t solve the issue, it shall be ~₹15,000 down the drain”. This thought was haunting me day-in and day-out. I was using the car daily for 25 kms (with those jerks) – No clear solution available. In 11 days got a call saying that the Flywheel Assy had arrived at the MOBIS outlet we ordered from and I came come to collect if I want. I kept it on-hold since I wasn’t convinced that its replacement is the solution and is connected to this jerking issue.

[a4anurag]

We decide to shift focus and look into other components like

• Faulty clutch switch (Hyundai calls it Ignition-lock switch) - The clutch switch was an important checkpoint since the description in the service manual said:

  Clutch operation is detected through the clutch switch and this signal enables the ECM to cope with instant change of load conditions and is used to detect engaged gear with vehicle speed and engine speed.

  Clutch pedal and the clutch switch
  
  
  After checking the clutch switch, all was okay and no difference to the jerking issue.
  
  
• Faulty ABS (wheel speed) sensor – Disconnected the two ABS related fuse from the engine compartment fuse box and drove on a desolate road to see if any difference was observed but no, the jerking issue was very much present.

All this while, I had the scanner plugged-in recording everything in the hope of pinpointing the issue. The following parameters were being recorded (engine load, fuel injection quantity, boost, MAF, RPM, accelerator pedal position, battery voltage, gear position, clutch position, clutch pushed more than 10%). During one such drive after a few days, we saw something unusual happen coinciding perfectly with the jerking issue and that was “the” moment for us, literally! We had struck gold!

Scanner read:
Gear is on Neutral Position (M/T Only) = YES
Gearbox Neutral Position Status Signal = ON

Scanner Displaying the culprit that we were searching for

In reality, the gear lever was in 4th and the car was at 55kmph but the gearbox was sensing that the lever is in Neutral (N) giving that information to the ECU. Returned home with a positive feeling as something has been found finally which was causing both of us mental irritation from the past 4 months.

• Another dead giveaway which we somehow missed all this while was the absence or erratic behaviour of gear-shift suggestion indicator in the MID that was coinciding with the engine jerking issue.
  
  
• Since the Hyundai Creta doesn’t get a dedicated gear position sensor, it relies on engine RPM and vehicle speed to calculate the exact gear which has been selected. It takes the data from the clutch switch, ABS module (for vehicle speed), engine RPM and neutral switch to figure out the exact gear and anticipate driver’s intention to modify fuelling.
  
• In the video that I have uploaded in the first post, from 00:00-00:29, no upshift suggestions are observed. From 00:30 onwards till the video ends, it displays the suggestion once hence the violent shaking stops and the car is smooth. All that while the Neutral Switch was giving data to the ECU as if the gear is in Neutral.

To gain access to the neutral switch that is located on the gearbox facing the radiator, the air filter box has to be removed. The neutral switch is a small pin-like unit that moves In & Out working like an on-off switch thereby informing the ECU if the gearbox is in Neutral or in gear.

The Neutral Switch as highlighted in yellow


OEM Neutral Switch

Using a 24mm spanner, removed the switch and first, we checked was for continuity – it was open circuit. Checked the resistance and found it be 8 kilo-ohms.

Neutral Switch description (from the service manual):

Neutral gear switch is installed in M/T vehicles (ISG system or Diesel engines) and senses driver’s intention to shift gear. When the vehicle starts to move after standing for a while and vehicle speed does not reach to 2 kmph, fuel quantity mapping value at neutral gear is adopted to the vehicle. Moreover, this phenomenon is more serious when the vehicle requires high power generation such as a situation when the vehicle is on the slope. To cope with this problem, neutral gear switch which senses the driver’s intention of starting to move is applied and fuel injection quantity mapping value suitable for 1st gear is adopted immediately.

Searched for it on Boodmo and went to the MOBIS outlet armed with the part details:

Part Name: Switch Assy – Backup Lamp (Neutral Switch)
Part Number: 93860-39012
Price: ₹1,958.00

This part is a fairly common one and is used in most Hyundai cars made so far – Eon, Getz, i10, i10 Grand, i20, i20 Elite, i20 Active, Accent Viva, Elantra (3rd gen), Elantra (5th gen), Elantra (6th gen), Creta, Sonata, Terracan, Tucson, Verna, Verna Fluidic and Xcent.

The MOBIS outlet which we went to, ironically did not have it in stock. They had asked us to come after 1-2 days so they could arrange it for me. Since it was available on Boodmo and it said ‘1-day delivery’, I decided to place an order there as well. While browsing the parts applicability list, there was something that caught BHPian interc00led’s eyes, the same part was available in the ‘Aftermarket Parts’ section of the listing with the real image matching the part we were looking for:

Part Name: Reverse Light Switch
Part Number: TD-1114
Price: ₹266.00

Uno Minda Switch Price


Uno Minda Switch (labelled as Reverse light switch - Accent)

I had lost trust that Boodmo's delivery system (XpressBees) could deliver the switch in-time as promised. The reason was, I had placed 3 orders earlier which was ‘Boodmo fulfilled’ plus the App did say ‘1-day delivery’ but only 1 package got delivered rest items were getting postponed so had to cancel and get a refund. For the heck of it BHPian interc00led checked for the same Uno Minda part on Amazon.in and we were lucky to have that part available (last piece) which was sold by ‘Cloudtail & also 1-day delivery with PRIME’. Immediately placed an order (Saturday) and got the delivery on Sunday.

After receiving the switch, we checked the continuity - it was okay and the resistance was less than 2 ohms. Since it was a weekend, we had met at the garage to fit the switch and it took us roughly 15 minutes. After everything back in the car, when we drove off the garage, both of us were enlightened that the jerking issue had disappeared and it was smooth as it should be (odometer: 81,563 kms). Since the old switch was of no use, we broke it down to see what is inside and any pointers that we could get from it. When the resistance was checked, it displayed a reading of 1.46 Mega Ohms (an increase from 8 Kilo Ohms when it was last checked). IMHO the switch gave up completely making the ECU think that the car is Neutral always.

Resistance as measured before dismantling the switch


OEM Neutral switch dismantled

For the first time since March, i.e. 5 months & 3 days later we were literally happy and relieved after finding the culprit that had caused enough havoc. Having driven the car with this issue for ~7,000 kms, I started to hate it and wouldn't want to take the car out (not that I had a choice but still). Our FNG owner whom we were in constant touch with and updating him about the issue was also surprised that a simple switch was creating such an issue in terms of driveability. He hasn’t come across such violent jerks ever in any car during his entire career.

Odometer where all the misery ended and the car has been normal since then

• Since the culprit has been found, what I can’t understand is what was going in the mind of those engineers @ Hyundai when they decided to use this great switch to link the ECU and fuel to such an extent that the whole car is just un-driveable.
  
  
• Also as per the ‘Neutral Switch’ description, being an important link in the whole setup, why no Check Engine Light (CEL) was given or thought for?! Fuelling was going haywire, I assume, as the ECU was suspecting the gear to be in Neutral yet load and vehicle speed was being detected causing the vehicle to go bonkers.

Current odometer is 82,200 kms and has been a delight to drive so far with no occurrence of the jerking since then.

[moralfibre]

Thread moved from the Assembly Line to the Technical Stuff Section. Thanks for sharing!

[sagarpadaki]

Good troubleshooting Anurag.

I know how frustrating it is when there is an issue and we are not able to identify the root cause. Finding the root case is 90% of problem solved.

And as usual, the simple part is overpriced 10 times by Hyundai

[DragonHawk]

Thanks, Anurag for giving a different pointer to the jerk issue.

Couple of weeks back I had a similar issue in my ecosport, alebit jerk was seen only when I depress clutch and when car is moved in 1st gear with the half-pressed clutch. In my case jerk was more or less comparable to miss fire seen in bikes. Ford ASC suspected it might be wiring harness, however I and one of the main techs were not fully convinced and thought to give a try by replacing clutch pedal and clutch switch. Initially, clutch switch was replaced with the one taken out from TD car and voila it solved the problem.

[d3mon]

Originally Posted by a4anurag

[*]Also as per the ‘Neutral Switch’ description, being an important link in the whole setup, why no Check Engine Light (CEL) was given or thought for?! Fuelling was going haywire, I assume, as the ECU was suspecting the gear to be in Neutral yet load and vehicle speed was being detected causing the vehicle to go bonkers.[/list]

Great detective work there! As you noted, it seems unacceptable for Hyundai not to monitor the health of this signal that's routed to the ECU. Most manufacturers would have thrown an "implausible signal" code if the signal value was behaving erratically as it was in your case.

I guess Hyundai subscribes to the "If it ain't broke, why throw a code?" philosophy that would reduce their warranty & repair costs. This is in stark contrast to the Germans who are the exact opposite, throwing a code even if they detect you woke up on the wrong side of the bed.

[poised2drive]

As usual, this is one more guide for the Creta owners to check out the possible issues.

And being there with you when you were trying to figure out the problem in the FNG, I must say I was awed by your unmitigated passion towards your cars. No wonder, you churn out threads on DIYs as a piece of cake.

And if you remember, I said I have encountered a similar issue in my friend's Nexon. During upshifts to 3rd/4th gear @ 2000 RPM , there are jerks, albeit not that violent as observed in your Creta and only I could feel it.

I hope you could throw some light on it once you drive the vehicle.

[extreme_torque]

Excellent diagnosis! Which OBD app did you use? It does sound obtuse that they would link fueling with this switch but then again I dont know how they handle it in others. As they say the root of the problem is usually lie in small things and these new age engines are pretty complex pieces of machinery and electronis.

[ike]

A simple switch did hold you to ransom. Is the gear indicator is also back to normal now? I'm assuming it should be since there are no jerks.

[a4anurag]

Originally Posted by poised2drive

And if you remember, I said I have encountered a similar issue in my friend's Nexon. During upshifts to 3rd/4th gear @ 2000 RPM , there are jerks, albeit not that violent as observed in your Creta and only I could feel it.

Let's get to drive the car when you come to Hyderabad next time. Hopefully we can locate the problem faster.

Originally Posted by extreme_torque

Which OBD app did you use

It is the Launch X431 PRO. This diagnostic tool that we use mimics the G-Scan II completely in terms of functionality which Hyundai uses at the OEM level.

Originally Posted by ike

Is the gear indicator is also back to normal now? I'm assuming it should be since there are no jerks.

Yes sir, everything is fine and gear shift recommendations are appearing in every gear as it used.

[Jag4]

Originally Posted by a4anurag

We decide to shift focus and look into other components like


Part Name: Switch Assy – Backup Lamp (Neutral Switch)
Part Number: 93860-39012
Price: ₹1,958.00

This part is a fairly common one and is used in most Hyundai cars made so far – Eon, Getz, i10, i10 Grand, i20, i20 Elite, i20 Active, Accent Viva, Elantra (3rd gen), Elantra (5th gen), Elantra (6th gen), Creta, Sonata, Terracan, Tucson, Verna, Verna Fluidic and Xcent.

Part Name: Reverse Light Switch
Part Number: TD-1114
Price: ₹266.00

Uno Minda Switch Price
Attachment 2044236

Uno Minda Switch (labelled as Reverse light switch - Accent)
Attachment 2044237

Great work there Sir ! Must be a relief after hours of endlessly toiling over the needle in the haystack.

This exact switch on my 2012 i20 Crdi used to cause the engine to die and shutdown randomly when the clutch pedal was pressed for changing gears.
Sometimes even at speeds of 40/50km/h !

However, I took it straight to the service centre and they were able to point out the fault through the diagnostic tool. It took them 2 hours but saved me quite a lot of money from what it seems.

They had performed some tomfoolery/witchcraft to the switch two years ago (and told me they had just cleaned it) but recently after 2 years, the issue has started cropping up again.

Thanks for the sharing the part number for the UNO MINDA alternative, I will get it replaced asap !

[a4anurag]

Originally Posted by Jag4

Thanks for the sharing the part number for the UNO MINDA alternative, I will get it replaced asap !

Haha yes, the Uno Minda switch came as a blessing. Details of the switch from Boodmo.



This switch should be available locally, one needs to ask it as - Hyundai Accent reverse switch.

[steadfast]

For all such errors, I always prefer taking the car to authorised workshop and once the error is zeroed on by company, I contact the FNG workshop for replacement parts.

Ideally, this approach saves lot of time, money and irrelevant replacements. Cars are not the best trial and error test beds

[a4anurag]

Had forgotten to upload a video at the end of the post displaying the gear-shift suggestion in the MID after everything was alright.

Suggestion for upshifting being displayed


Suggestion for downshifting being displayed


A small video:

https://youtu.be/ZMQarloejFM

Originally Posted by ike

Is the gear indicator is also back to normal now? I'm assuming it should be since there are no jerks.

Attached a video and two images of the gear shift indicator suggestion on the MID.

Originally Posted by steadfast

For all such errors, I always prefer taking the car to authorised workshop and once the error is zeroed on by company, I contact the FNG workshop for replacement parts.

Thank you for the suggestion sir, but, I'll prefer to do things myself with help of my FNG than visit the ASC. With the current situation and rush of vehicles at the ASC, I didn't want to keep the car with them ON HOLD till they could trace the issue.

Originally Posted by steadfast

Cars are not the best trial and error test beds.

When manufacturers use customers as guinea pigs as test beds, that is what worries me more than anything else. Especially the initials batch owners of new launches.

[arijitkanrar]

My first guess when you described the jerking was a fueling issue. May be a clogged injector or something.
But I would've never thought that a faulty switch would indirectly cause incorrect fueling.
Very good analysis sir. Happy that you were able to hunt it down.
Enjoy your car now as in the course of this exercise you have inadvertently changed a few parts for the good.