How The 10 Worst Audi G28 Fails Of All Time Could Have Been Prevented
How The 10 Worst Audi G28 Fails Of All Time Could Have Been Prevented
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How to Replace an Audi G28 Engine Speed Sensor
Charles the Humble Technician teaches how to replace the G28 Engine Speed Sensor. This sensor is located at the top of the transmission, above the flywheel ring gear. It transmits a signal to the ECU via the grey wire (T55/49) and then to the tachometer located in the instrument cluster.
1. Engine Speed Sensor
Located on the edge of the transmission just above the flywheel ring gear, the G28 Engine Speed Sensor sends an electrical signal to ECU pin T55/49 through a grey wire. The ECU then uses this information to control the flow of fuel, timig and boost. It also sends an alert to the G5 Tachometer in instrument cluster.
The sensor is used as a reference to correlate with the G40 Camshaft Position Sensor. The ecu must be aware when the crankshaft is TDC and where the camshaft is located so that it can trigger spark and injectors accordingly.
If this sensor fails, the ECU will display the P00160 error, which means the Crank Shaft and Intake Camshaft are not in sync and could indicate the chain stretching or a jump link on the upper timing chain. The code will not appear without the additional information provided by other sensors (G4 or G40).
It's a bit tricky to test as there are various connector pins, and each one has different functions. The most effective method to test it is to measure the resistance between the ECU and the sensor. When the sensor is fully operational, it should be reading approximately 1000 ohms. Look for evidence of coolant or oil in the connector bay if you are experiencing problems with this part.
2. Injectors
Yesterday, while accelerating at full speed from the highway paytoll i had a big cut in power like the engine is out of gas or injectors are not firing at all. This morning i pull out the spark plugs, three were drenched in gazoline, the fourth was dry. I placed a tissue over each hole in the injector and when I turn the engine on without sparks, the 3 with gazoline jump out. The fourth one remains closed. I tried to test the ground connections of ECU pins 14,30, and 48/55. I got 0ohm. Therefore, i think the issue is somewhere else.
I also tried to reset the PID without success. The car will start when the G28 is disconnected and is running fine when it is connected however it is experiencing intermittent misfires at higher RPM. The temperature sensor for coolant (G62) shows the wrong temp value -49c even when i unplug it. I also noticed that the oil pressure gauge in the cockpit is showing 2 bar, whereas the actual pressure is 0.0 when i rev website the engine.
I'm not certain what to do, i believe that i've completely ruled out all other possibilities. I'm worried that i might have missed something. If anyone has any ideas please let me know! TIA!
3. Fuel Pump
The fuel pump of the g28 receives a signal from the RPM sensor. The GM-style transmitter is similar to the G4 sender, and both operate on the 80,100,200, UrS, and RS2 vehicles. It is easy to find a spare in a wrecking shop or parts store. It is easy to here test them: simply put your DMM into resistance mode and determine the distance between pins 1 and 2 (with the click here bump at the connector's end facing upwards). They must be infinite ohms.
4. ECU
Our 20vt turbo (3B AAN, ABY and ADU) engines have an ECU that needs to be aware of the speed and position of the crankshaft to make a decision about fuel injector timing etc. To do this, it utilizes a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If either of these sensors go badly, you audi a1 keys will see codes on the diagnostic scanner which could cause engine shut down.
A malfunctioning G28 sensor could result in an inaccurate gearbox speed counter, a gearbox that shifts more quickly than normal, and/or a misfire while in the gear. It is likely that the sensor is failing and needs to be replaced if you encounter any of these symptoms. The good news is they are quite affordable and easy to find particularly if you're looking at the Bosch unit like ours. Alternatively, the GM version of this component read more is also a good option.
5. Tachometer
A faulty engine speed sensor could be a cause for many problems in your vehicle. It is an important part of the transmission of your Audi because it relays information to the ECU on how fast or slowly the engine of the car is spinning. This sensor can cause the transmission to malfunction and other car components to be affected.
The G5 engine speed sensor is located on the outside of the transmission just above the flywheel ring gear and transmits a signal to the ECU at pin T55/49, via an uncolored wire. The ECU then uses and processes this signal to regulate fuel, timig, and boost, and also transmitting it to the G5 tachometer inside the instrument cluster. You can determine if the sensor is in failure by examining the continuity of the sensor to the tachometer. You can also examine the continuity between pins T55/49 of the ECU and pin T6a/1 of the instrument cluster (trace [79]) and between pin T6a/1 and pin T26a/12. There should be an average resistance of 1000 ohms between these points. This is the same across the Audi 80-100-200-RS2 series, starting beginning with the 1985 MC and up to the 1997 UrS An and 1995 RS2 DU So, you may find some good ones in wrecking yards.