Within a few weeks of writing my last article, I had a body shop call us to help with one of their customers’ cars. The body shop stated they had a 2012 Audi Q5 2.0T that was hit in the front. Once the car was put back together, the engine was running rough, and the check engine light was on. The body shop had connected a scanner and pulled lean and camshaft position codes. They asked us for help, and we told them to get us the car as soon as possible.
If you remember, in my last article, I wrote about a customer who had a 2012 Audi A4 2.0 liter that was not starting. The customer tried to do some basic repairs but ended up causing more problems. The reason I’m bringing up my last article will make itself evident soon. In my last article, the customer tried to check his oil but lost the dipstick tube cap, which caused a breather leak.
After getting the 2012 Audi Q5 2.0T from the body shop, we connected it to the Audi factory tool. We pulled multiple codes. We pulled P2279: intake air system leak; P052A: cold start A camshaft position timing over-advanced; P0011: A camshaft position bank 10 timing over-advanced or system performance; and P0234: turbo supercharger over boost condition.
Before I got too deep into this diagnosis, I expressed my concern to the customer about the camshaft position codes. The Audi and VW 2.0 liter motors are prone to jumping camshaft chains once the chain gets worn out. Because this car was hit in the front end, I was concerned that the impact may have caused severe damage to the engine’s timing system.
Lean conditions are a major problem on Audi engines, so that is where we started.
We performed a crankcase pressure test. We measured an abnormally large amount of vacuum. We then performed a smoke vacuum test. A very small amount of smoke was coming from the front of the engine area. The smoke coming from the front of the engine was from a broken turbo wastegate control solenoid. The wastegate control solenoid was broken because of the accident. The amount of smoke from the broken solenoid could not justify the readings we were getting on the crankcase pressure test. We then checked the oil separator (breather). The production date on the breather showed us that it was original. There was no external damage to the breather, but the front-end impact may have dislodged the breather’s diaphragm.
We then replaced the breather first and retested the crankcase pressure before replacing the wastegate solenoid. With the new breather, the crankcase vacuum pressure dropped by 60%. We then replaced the wastegate solenoid, but the crankcase pressure only dropped another 5%. We then performed a smoke test with the new breather and wastegate solenoid. We then saw smoke coming out of the center of the dipstick tube. When we looked closer at the dipstick tube, we saw a crack in the center of the tube where the radiator support hit it. Because the dipstick tube was just cracked and not broken, it did not leak smoke until we had replaced the breather and the wastegate solenoid. The top of the dipstick tube has a bracket connected to the camshaft magnet. Looking closely, we could see that during the accident, the front radiator support damaged the dipstick tube, the cam magnet and the wastegate solenoid. We then replaced the dipstick tube and camshaft magnet.
The dipstick tube was the final puzzle piece to solve the P2279 lean condition and unraveled the camshaft codes. The wastegate solenoid solved the P0234 turbo boost issue and part of the lean code. The camshaft magnet solved the P052A camshaft code and the P0011 camshaft position code. I found the process all extremely interesting because of the way the accident affected so many of the Audi’s engine systems.
Matt Pataky owns Sunnyvale Foreign Car Service, 15 Pioneer Way, Mountain View. For more information, call (650) 960-6988, email [email protected] or visit sunnyvaleforeigncar.com.
