10 Mistaken Answers To Common Audi G28 Questions Do You Know The Right Answers?

How to Replace an Audi G28 Engine Speed Sensor

Charles the Humble Technician shows 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 a grey wire T55/49, then to the tachometer in the instrument cluster.

1. Engine Speed Sensor

The grey wire is located at the edges of the transmission, directly above the flywheel ring. The sensor transmits an electrical signal through the grey wire to pin T55/49. The ECU uses this information to regulate boost and fuel. It also sends an indication to the G5 tachometer in the instrument cluster.

The sensor is used to correlate with the G40 Camshaft position Sensor. The ecu needs to know when the crankshaft is TDC and where the camshaft is so it can start spark and injectors in the right way.

If this sensor fails to function, the ECU will display a P00160 error code. This means that the Crank Shaft is out of sync with the Intake Camshaft. It could also be a sign of an issue with the chain or a jump in the chain link of 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 can be a bit difficult to test because there are various pins on the connector and each has its own functions. The best way to do it is by measuring the resistance between the ECU and the sensor. If the sensor is functional, it should read about 1000 ohms. Check for evidence of coolant or oil in the connector bay if you have problems with this part.

2. Injectors

Yesterday, while accelerating at full speed from the highway paytoll, i experienced an abrupt drop in power as if the engine was running out of gas or injectors aren't firing at all. I took out the spark plugs this morning, 3 were soaked in gasoline, and the fourth was unclean. I placed a tissue over each injector hole, and when I start the engine with no sparks, the ones with gazoline jump out. The 4th one stays shut. I checked the ground connection of ECU pins 14,30 and 48/55. I got 0ohm. I'm assuming the issue is in another place.

I also tried to reset PID without success. The here car will start when the G28 is unplugged and is running fine when it is plugged in however it is experiencing intermittent misfires at higher RPM. The coolant sensor (G62), even when unplugged, still shows an ice more info temperature of -49c. Also, i noticed that the gauge for oil pressure in the cockpit shows 2 bar while the actual pressure is 0.0 when i rev the engine.

I'm not certain what to do, as i think i've pretty much ruled out everything else. But i am afraid I might have read more missed something. If anyone has suggestions, please let me know! TIA!

3. Fuel Pump

The fuel pump of the g28 receives a signal from the RPM sensor. The GM-style sender is identical to the G4 and both are used in the 80 100, 200, UrS and RS2 cars so you can easily find one get more info at a wrecking yard or at a parts store. It is easy to test them: simply switch your DMM into resistance mode and determine the distance between pins 1 and 2 (with the bump at the connector's end facing up). They should 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 to make decisions regarding fuel injector timing, etc. It utilizes a Crank Position Sensor G4 and an Engine Speed Sensor G28 to accomplish this. If either of these go badly, you will see codes on the diagnostic scanner which can lead to engine shutdown.

The signs of a malfunctioning G28 sensor are an inaccurate rev counter in the gearbox the gears are shifting faster than normal and/or misfiring when you are in gear. If you have any of these issues, it is likely your sensor is failing and should be replaced. They're inexpensive and easy to locate especially when they're a Bosch sensor like ours. Alternatively, the GM version of this part is also a good choice.

5. Tachometer

A malfunctioning engine sensor can cause a myriad of issues in your vehicle. It is an important part of the transmission of your Audi since it sends information to the ECU regarding how fast or slow the engine is turning. If this sensor fails, it will disrupt the performance of the transmission and the rest of the car's components.

The G5 engine sensor is located at the edge of the transmission, over the flywheel ring. It sends audi keys a signal via an uncolored wire to the ECU pin T55/49. The ECU then processes this signal to regulate fuel, timig, and boost and then sends it on to the G5 Tachometer located in the instrument cluster. You can check for sensor 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 [79]), and between pin T6a/1 and pin T26a/12. You should observe approximately 1000 ohms resistance between those points. This is a common feature across the Audi 80-100-200-RS2 model, ranging beginning with the 1985 MC and up to the 1997 UrS AN and the 1995 RS2 Du You may also find some good ones in wrecking yards.