My Hyundai i20 Turbo's check engine light comes on: Error code P007100

I took the car to the service centre but the mechanic had no clue what to do about the problem.

BHPian goandude recently shared this with other enthusiasts.

While driving my 2-year-old Hyundai i20 Turbo 1.0 IMT with about 12k km on the odo, CEL comes on. Car is running flawlessly and giving good mileage.

Took it to Advaith Hyundai in Indiranagar (it was 5th February Sunday) where a technician connected the OBD and the error code was P007100. (Ambient Air temperature circuit range /performance).

He was clueless about what to do about it. He cleared the error code, and I didn't insist he does anything else, seeing his incompetence. Anyway, he said if it happens again we will change the sensor. I drove off and CEL did not come on again.

Till 28th February while I was driving Mysore to Bangalore when again the CEL lit up. Drove the rest of the 150 odd kms straight to Advaith Hyundai and the same technician was there and this time the same DTC code showed up.

This time he says we need time to check the sensor so leave the car here and we will get back to you. However, due to other reasons I couldn't, so he cleared the code again. And I carried on with my journey of another 160 kms in the next 2 days without the light coming on or any other issues with the car.

The Ambient temperature sensor is located in front of the radiator and gives the information to ECU, which processes it further. This temperature info is also presented on the MID. Knowing this, I monitored the temperature regularly and it was quite accurate. So I'm at a loss to see how the sensor has failed. Moreover, if it has failed / loose connection, why does the CEL stay off after getting the DTC cleared?

Another thing, maybe a coincidence, both times the CEL came on shortly after filling in petrol. Not immediately but after a few km.

Can anyone suggest my further course of action? Thanks.

Here's what BHPian Jeroen had to say about the matter:

When you get a sensor-related error like this and it appears intermittent I'd always check the wiring and connectors first. Pull the connectors in the wiring to the sensor, clean them if necessary. Check all the wiring for chaffing and so.

A problem like this can be caused by high resistance in the circuit. E.g. a corroded connector, or an exposed/chaffed wire touching to ground.

Last resort would be to replace the sensor. You might be able to measure and check the sensor before replacing too.

Here's what BHPian scorpian had to say about the matter:

Replace the sensor, it could be failing.

I had a map sensor fail in my car and replaced it with a new one and had the same CEL coming on again and again. The new sensor was also defective. After replacing it again the CEL didn't come on again.

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