(Coolant temperature if fuel temperature sensor fails)Īdjustment temperatures are approximately: The over riding factor for adjusting these maps is Fuel temperature. The engine ECU may be relying on 6 Duration maps and 10 Beginning of Injection maps for Injection Quantity. The Fuel and coolant temperatures are far more important than you might think. If the air intake temperature is considerably different to ambient temperature, change the Air Intake Sensor. If the fuel temperature graph looks odd or goes too high/low, change the fuel temp sensor.Īir intake temperature should be similar to the outside temperature on the day of test and should stay constant. Pre CAN vehicles like the B5 passat cannot self diagnose a cooling problem so you have to do a test like this.ĬAN vehicles like the B6 passat will flag a fault code if the engine ECU detects that the warm-up graph is incorrect.Ī Fuel temperature graph should look the same as the coolant graph. I have only included Coolant temperature to make it easier to read. The excel graph will look something like the one below. You need to turn this log into an excel graph. This will be a very long log which has Time Stamp as one of the columns. When you get back, save the log you have produced. Go for at least a 20 minute drive to bring the engine up to working temperature. Start the engine from COLD and select log START. This assumes you know how to engine measuring blocks.Ī good, first check, is the engines coolant, fuel and air temperatures as these are very important for fuelling.įind the block that displays temperatures. It is advisable to fit a new air filter and fuel filter before running any checks. Injector diagnosis (You can't diagnose injectors using VCDS) The following measuring block checks will help you investigate an engine problem that hasn’t logged a fault code. Pre CAN control engines tend to need more diagnosis while CAN control engines do more self diagnosis. The information here is only a general guide as there is variation between engines. It is a good idea to log your engine when it is healthy so that you have something to use for comparison when your car is not healthy. This guide applies to most VAG pd tdi engines.

Vcds measuring blocks list