How to Replace an Audi G28 Engine Speed Sensor
In this video, Charles the humble mechanic demonstrates how to replace the G28 engine speed sensor. This sensor is located on the edge of the transmission just above the flywheel ring gear. It sends a message to the ECU through an uncolored wire T55/49, then to the tachometer on the instrument cluster.
1. Engine Speed Sensor
The grey wire is situated on the edge of transmission, just above the flywheel ring. The sensor transmits signals through the grey wire to pin T55/49. The ECU then utilizes this information to regulate the boost, fuel, and timig. It also sends an indicator to the G5 Tachometer within the instrument cluster.
The sensor is used to correlate with the G40 Camshaft position Sensor. The ecu must know when the crankshaft is TDC and the location of the camshaft so it can activate spark and injectors accordingly.
If this sensor fails the ECU will show an error code P00160 which indicates that the Crank Shaft and Intake Camshaft are out of sync, possibly indicating the chain stretching or a jump link on the upper chain of timing. However, the error code won't appear on its own without additional information from other sensors (G4 and G40).
It's a bit tricky to test since there are various 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 if the sensor is operating at its maximum. Check for evidence of coolant or oil in the connector bay if there are issues with this part.
2. Injectors
Yesterday, while accelerating at full speed from the highway paytoll i had an abrupt drop in power as if the engine was running out of gas or injectors are not firing anymore. In the morning, i removed the spark plugs, 3 were drenched in gazoline, the fourth one was dry. When I crank the engine without sparks, i place a tissue on top of each injector hole, the 3 drenched with gazoline pop out, but the 4th stays shut. I checked the ground connection of ECU pins 14,30, and 48/55. I got zero ohm. I assume audi key programming near me that the problem is somewhere else.
I also tried to reset the PID with no success. The car will start when the G28 is unplugged, and it works fine when the G28 connected. However, the intermittent misfire problem continues to occur at higher RPM. The coolant sensor (G62) even when it is unplugged, shows a temperature of -49c. Also, i noticed that the oil pressure gauge in the cockpit shows 2 bar when the actual pressure is 0.0 if i crank up the engine.
I don't know what to do. I believe that I've all other possibilities out. I'm concerned that i may have missed something. If anyone has any ideas please let me know! TIA!
3. Fuel Pump
The fuel pump in the g28 audi tt keys is activated by a signal sent from the RPM sensor. The GM-style transmitter is the same as the G4 and both function in the 80 100 200, UrS and RS2 cars which is why you can easily locate one at a wrecking yard or from a parts store. Testing them is easy replacement key for audi a3 - put your DMM in resistance mode and measure between pins 1 (with the bump on the connector end up) and 2 (2nd from the left on the black connector's end). They must be infinite Ohms.
4. ECU
Our 20vt turbo (3B AAN, ABY, and ADU) engines have an ECU that needs to know the position and speed of the crankshaft to make decisions about fuel injector timing etc. It utilizes a Crank Position Sensor G4 and an Engine Speed Sensor G28 to achieve this. If either of these goes badly, you will see codes on the diagnostic scanner that can cause the engine to shut down.
A damaged G28 sensor can cause an inaccurate speed counter for your gearbox, a gearbox that shifts more quickly than normal, and/or an unfire when in the gear. If you experience any of these issues, it is likely your sensor is failing and needs replacing. They're inexpensive and easy to locate especially if they're a Bosch sensor like ours. Alternately, the GM version of this part is also a good option.
5. Tachometer
A faulty engine speed sensor could be a cause for a slew of issues in your car. It's a vital component of your Audi's transmission, as it sends information to the ECU about how the car's crankshaft is rotating. When this sensor fails, it will affect the performance audi a1 car key of the transmission, as well as the rest of the car's components.
The G5 engine sensor is located at the edge of the transmission, just above the flywheel ring. It sends an electrical signal through gray wire to ECU pin T55/49. The ECU uses this signal to regulate the amount of fuel and boost, and also to timigrate. It also sends it to the G5 Tachometer located in website the instrument cluster. You can test the sensor for failure by checking continuity between it and the tachometer, between the ECU pin T55/49 and the instrument cluster connection on pin T6a/1 (trace [79]) and between T6a/1 and the instrument cluster pin T26a/12. You should observe approximately 1000 ohms resistance between those points. This is a standard part across the Audi 80, 100, 200, UrS and RS2 range from 1985 MC until the 1997 UrS AAN and 1995 RS2 ADU so good ones could be available in wrecking yards.