The 10 Worst Audi G28 Fails Of All Time Could Have Been Prevented
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
In this video Charles the Humble Mechanic shows how to replace the G28 engine speed sensor. This sensor is situated at the edge of transmission just above the flywheel gear. It transmits a signal to the ECU via a grey wire T55/49, then to the tachometer on the instrument cluster.
1. Engine Speed Sensor
Located on the edge of the transmission above the flywheel ring gear the G28 Engine Speed Sensor sends a signal to ECU pin T55/49 via an uncolored wire. The ECU then uses this information to control the boost, fuel, and timig. It also sends a signal to the G5 tachometer in the instrument cluster.
The sensor is used to connect the G40 Camshaft position Sensor. The ecu has to know when the crankshaft reached TDC, and where the camshaft lies in order to activate the spark and injectors.
If this sensor fails, the ECU will display a P00160 code which means the Crank Shaft and Intake Camshaft aren't in sync, possibly indicating the chain stretching or a jump link on the upper timing chain. However, the code won't appear on its own without additional information from other sensors (G4 and G40).
It's a bit tricky to test because there are several pins on the connector and each has its own functions. The most effective method to test it is to measure the resistance between the ECU and the sensor. It should read around 1000 ohms when the sensor is operating at its maximum. If you're experiencing issues with this part, check for signs of coolant or oil in the connector bay.
2. Injectors
Yesterday, while accelerating at full speed from the highway paytoll, I experienced a big cut in power as if the engine was running out of gas or the injectors aren't firing anymore. 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 start the engine without sparks, the ones that have gazoline pop right out. The 4th one remains shut. I inspected the ground connection on ECU pins 14/55,30/55 and 48/55 i get 0ohm. I assume that the problem is somewhere else.
I also tried to reset the PID with no success. The car is able to start when the G28 is not plugged in and it runs perfectly when it is plugged in however it has intermittent misfire issues at higher RPM. The coolant sensor (G62), even when unplugged, still shows an ice temperature of -49c. I also noticed that the oil pressure gauge in the cockpit shows 2 bar, whereas the actual pressure is 0.0 if i crank up the engine.
I'm not certain what to do, but i feel i have pretty much completely ruled out all other possibilities. I'm afraid website i may have missed something. If anyone has any ideas please let me know! TIA!
3. Fuel Pump
The fuel pump on the g28 is activated by a signal sent from the RPM sensor. The GM-style transmitter is identical to the G4 sender and works on the 80,100,200, UrS, and RS2 vehicles. You can easily locate an extra in a wrecking shop or a parts store. Testing them is easy to do - just put your DMM in resistance mode and take measurements between pins 1 (with the bump on the connector end up) and 2 (2nd from left on the black connector's side). They must be infinite Ohms.
4. ECU
The ECU in our 20vt turbo (3B AAN ABY) engines must know both the position and speed of the crankshaft in order to make a decision about fuel injector timing, etc. To do this, it makes use of a Crank Position Sensor (G4) and an Engine spare audi key cost Speed Sensor (G28). If either of these go wrong, you will receive codes on the diagnostic scanner which can lead get more info to engine shutdown.
A failing G28 sensor could cause an inaccurate gearbox speed counter or a gearbox that shifts faster than normal, or a misfire in gear. It is possible that your sensor is failing and needs to be replaced if you notice any of these signs. They're cheap and easy to find especially if they're an Bosch model like ours. Alternately, GM's version this part is an option.
5. Tachometer
A failing engine sensor could cause a number of problems within your vehicle. It's an essential component of the Audi's transmission because it communicates to the ECU about how fast or slow the car's crankshaft read more is spinning. If the sensor fails, it could disrupt the performance of the transmission, as well as the other car's components.
The G5 engine speed sensor is situated on the outside of the transmission, above the flywheel ring gear. It sends a signal to the ECU at pin T55/49 through a grey wire. more info The ECU then uses and processes the signal to control fuel, timig, and boost as well as transmitting it to the G5 Tachometer located in the instrument cluster. You can test the sensor for failure by examining the continuity between it and the tachometer, between the ECU pin T55/49 and the instrument cluster connection to pin T6a/1 (trace [79trace [79]) and between pin T6a/1 and the instrument cluster pin T26a/12. You should see approximately 1000 ohms of resistance between these two points. This is a typical part across the Audi 80, 100 200, UrS and RS2 range from 1985 MC through the 1997 UrS AAN and 1995 RS2 ADU so good parts could be found in wrecking yards.