Volkswagon Passat 2004, v5 AZX engine


Engine light on, ABS and traction control lights on.

The Vehicle had been bought to the workshop for the engine stalling when coming to a set of traffic lights, missing on take off, and no cruise control.


Scanning the vehicle With The Bosch KTS system showed many systems with faults. Mainly the Engine ECU with 12 fault codes, relating to; air mass meter high, missing cyl1, missing cyl2, throttle valve base setting, throttle valve control circuit faulty, Bank1 adaptation reached upper limit.

With these fault codes in mind we decided to clear the fault codes and test drive the vehicle to confirm if any faults where to come back straight away.
The Throttle valve fault code appeared after clearing the entire diagnostic system, a basic setting for the throttle valve can be done when; new ecu is fitted, throttle valve is cleaned, new throttle valve is fitted.

The throttle valve basic setting test was selected and the basics setting test failed, with this information in mind we decided to changethe throttle valve we rang up for a s/hand unit at $550 or a new throttle valve at $1250, the client decided that a new unit would be best as the s/hand unit only came with 3 months warranty.


The procedure from replacing the throttle body is easy you simply remove the air box and ducting, then remove the throttle valve remove the cooling hoses that are connected to the thorttle valve when you have access and replace the throttle valve with the new unit refit all parts in reverse order and start the vehicle

When the fitting of the throttle valve is complete, you need to carry out the basic setting and also the kick down setting on the new throttle valve, The Bosch KTS scan tool will aid in this procedure with step by step instructions. After completion of the basic setting the vehicle is to be driven to understand all of the new setting and configure the long and short term fuel trims.


The Missing and cruise control are now back to normal and the vehicle is idling correctly all due to the throttle valve being out of order and the basic setting not being set.