Automotive problems fixed: Audi engine stall; Citroen transmission; Fiat odours

In this article: We asked the leading technical supplier Autodata to share fixes on three common problems found in modern motor vehicles

The problem

We are struggling to diagnose a fault on a 2012 Audi A3 1.4 TFSI. In very cold ambient air temperature, the engine starts immediately after starting when the vehicle is parked overnight. The engine starts and runs fine after the car has been parked in the workshop for several hours. We have carried out some basic checks on the air and fuel systems and checked for any stored trouble codes but none were present. Have you heard of this fault?

The fix

Yes, we have been made aware of this fault in countries with cold climates. The fault affects A3 models with CAXC/CMSA engine codes. There is condensation build-up in the rear exhaust silencer that freezes overnight and prevents exhaust gas flow. To avoid water build up in the rear exhaust silencer, drill a water drain hole. This should be made with a 5mm drill using the following measurements: 1-86mm, 2-273mm, 3-5mm. This should rectify the fault.

The problem

We have a 2012 Citroen DS4 in the workshop which has an issue with the auto shift manual (ASM) transmission not engaging any selected gears. The starter motor also fails to operate intermittently. We have carried out some basic wiring checks but we haven’t found the cause of this fault. Have you any ideas where to start to fix this car?

The fix

Yes, we have come across the faults you have described before and they are due to poor earth connection on the transmission housing and a faulty chassis earth point due to corrosion. Remove the battery and battery tray. Locate and check the condition of the chassis earth point adjacent to the battery (1). Inspect the earth lead and earth point. Clean chassis earth point. Clean/tighten the battery earth point on the transmission housing. Refit the battery and battery tray. This should rectify the faults.

The problem

We have a 1.2 Fiat 500 in for service and we have noticed that there is a strong odour in the vehicle interior. The odour seems to be coming in from the engine bay area. The engine is clean and dry with no visible signs of oil or coolant leaks. We also checked the exhaust system for leaks and carried out an emissions test, all appears ok. Do you have any ideas?

The fix

The symptom that you describe is known to affect several Fiat models and the cause is due to crankcase breather hose being split or damaged. Remove the air filter housing to gain access to the crankcase breather hoses. Inspect the crankcase breather hoses for damage and replace if necessary (1 & 2). This should eliminate the strong odour in the vehicle interior.

This article is edited from an Autodata contribution to the February 2019 edition of the IMI's magazine.

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