Audi G28: The Good, The Bad, And The Ugly
Audi G28: The Good, The Bad, And The Ugly
Blog Article
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 situated at the edge of transmission, above the flywheel gear. It transmits a signal to the ECU via a grey wire T55/49, then to the tachometer located on the instrument cluster.
1. Engine Speed Sensor
The grey wire is situated on the edge of transmission, above the flywheel ring. This sensor sends an electrical signal through the grey wire to pin T55/49. The ECU uses this information to control fuel and boost. It also sends an indication to the G5 Tachometer located in the instrument cluster.
The sensor is used to connect the G40 Camshaft position Sensor. The ecu must know when the crankshaft has reached TDC and also the position of the camshaft, to trigger the spark and injectors.
If this sensor fails to function, the ECU will display a P00160 error message. This means that the Crank Shaft is not in line with the Intake Camshaft. It could also indicate an issue with the chain or a jumped chain link in the upper chain of timing. However, the error code won't appear on its own, without additional information from other sensors (G4 and G40).
Testing can be a bit difficult because there are two pins for the connector and they perform different functions but the most effective method of testing it is by measuring resistance between the sensor and the ECU. When the sensor is fully operational, it should read approximately 1000 ohms. If you are having problems with this part, check for evidence of coolant or oil in the connector bay.
2. Injectors
Yesterday, when i was accelerating to the fullest speed from highway paytoll, I experienced an abrupt drop in power as if the engine was running out of gas or the injectors are not firing anymore. I took out the spark plugs this morning, three were soaked in gasoline, and the 4th was dry. I put tissue over each injector hole, and when i start the engine without sparks, the 3 with gazoline jump out. The fourth one remains closed. I checked the ground connection of ECU pins 14,30, and 48/55. I found 0ohm. Therefore, i think the issue is somewhere else.
I also tried to reset PID without success. The car can start if the G28 is disconnected and audi spare key replacement is running fine when it is plugged in but it still is experiencing intermittent misfires at higher RPM. The coolant sensor (G62), even when unplugged, still shows an ice temperature of -49c. I also noticed that the oil gauge in the cockpit shows 2 bars while the actual pressure is 0.
I'm not certain what to do, but i think i've pretty much completely ruled out all other possibilities. But i am afraid I may have missed something. Let me know should you have any suggestions! TIA!
3. Fuel Pump
The fuel pump in the g28 receives a signal 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 so you can easily find one at a salvage yard or at a parts store. Testing them is easy - put your DMM in resistance mode and take measurements between pins 1 (with the bump on the connector end up) and 2 (2nd from the left on the black connector's side). They must be infinite Ohms.
4. ECU
The ECU of our 20vt turbo (3B AAN ABY) engines must know both the speed and position of the crankshaft in order to make a decision 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 which could cause engine shut down.
Some of the symptoms of a failed G28 sensor include an inaccurate gearbox rev counter, gears shifting quicker than normal and/or a misfire when you are in gear. If you are experiencing any of these problems, it is most likely that your sensor is failing and needs replacing. The good news is they are quite affordable and easily accessible particularly in the case of an Bosch model, which is what ours are. Alternatively, the GM version of this unit is also a good option.
5. Tachometer
A failing engine speed sensor could be the reason behind numerous issues in your car. It is a crucial part more info of your Audi's transmission, because it communicates to the ECU about how fast or slow the car's crankshaft is rotating. This sensor could cause the transmission to fail and other components of the car to be affected.
The G5 engine sensor is located at the edge of the transmission, just above the flywheel ring. It sends an electrical signal through an uncolored wire to the ECU pin T55/49. The read more ECU uses this signal to regulate the amount of fuel and boost, and also timig. It also sends it to get more info the G5 Tachometer located in the instrument cluster. You can determine if the sensor is in failure by checking continuity from the sensor to the tachometer. Also, you can check continuity between pin T55/49 of the ECU and pin T6a/1 of the instrument cluster (trace [79trace [79]), and between pin T6a/1 and pin T26a/12. You should see a resistance of approximately 1000 ohms between these two points. This part is common across the Audi 80-100-200-RS2 model, ranging from the 1985 MC up to the 1997 UrS AN more info and 1995 RS2 Du So, you may find them in wrecking yards.