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 near the transmission's edge just above the flywheel gear. It transmits a signal to the ECU via a grey wire (T55/49), then to the tachometer located in the instrument cluster.

1. Engine Speed Sensor

It is located on the outside of the transmission, above the flywheel ring gear, the G28 Engine Speed Sensor sends an electrical signal to ECU pin T55/49 via the grey wire. The ECU uses this information to regulate fuel and boost. It also sends an alert 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 where the camshaft is so it can activate spark and injectors in the right way.

If this sensor fails, the ECU will throw an error code P00160 which indicates that the Crank Shaft and Intake Camshaft are not in sync and possibly indicating the chain is stretched or a jump link on the upper chain of timing. The code won't appear without the additional information supplied by other sensors (G4 or G40).

It can be a bit difficult to test because there are several pins on the connector, and they all have different functions. The best way to do it is to measure the resistance between the ECU and the sensor. When the sensor is operational, it should be reading approximately 1000 ohms. Examine for signs of coolant, or oil in the connector bay if you have issues with this component.

2. Injectors

Yesterday, while accelerating from the highway paytoll at full speed I noticed a significant decrease in power. It was as if the engine was running out of gas. Or my injectors were not firing. Today, i pulled out the spark plugs, 3 were drenched with gazoline the 4th one was dry. When I start the engine, there are no sparks, I put a piece of tissue on the top of each hole in the injector and replacement audi key fob the 3 drenched with gazoline pop out, but the 4th stay closed. I checked the ground connection on ECU pins 14/55/30/55/48/55/14/55/48/ I get zero ohm. I assume that the problem is in another location.

I also tried to reset the PID without success. The car will start when the G28 is disconnected, but it is running fine with the G28 plugged in. However the intermittent misfire issue continues to occur at higher RPM. The temperature sensor for coolant (G62) shows the wrong temp value that is -49c even after unplugging it. I also noticed that the oil gauge in the cockpit shows 2 bar but the actual pressure is 0.

I'm not certain what to do, but i feel i have pretty much ruled out everything else. I'm afraid i may have missed something. Please let me know If you have any suggestions! TIA!

3. Fuel Pump

The fuel pump in the g28 gets a signal from the RPM sensor. The GM-style sensor is the same as the G4 and both are used in the 80, 100, 200, UrS and RS2 cars so you can easily find one at a wrecking yard or at a parts store. Test them out to do - just put your DMM in resistance mode and measure the resistance between pins 1 (with the bump on the connector's end up) and 2 (2nd from the left on the black connector's side). They must be infinite Ohms.

4. ECU

Our 20vt turbo (3B, AAN, ABY and ADU) engines are equipped with an ECU that has to be aware of the speed and position of the crankshaft in order to make a decision about fuel injector timing etc. In order to do this it utilizes a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If you have a problem with either one of these, the diagnostic scanner will display codes that could cause an engine shutdown.

Some of the symptoms of a malfunctioning G28 sensor are an inaccurate gearbox rev counter the gears are shifting faster than normal and/or a misfire when in gear. If you experience any of these issues, it is most likely that your sensor is going bad and requires replacement audi key Fob. They're inexpensive and easy to locate particularly when they're an Bosch model like ours. If you prefer, GM's version of this component is an excellent choice.

5. Tachometer

A malfunctioning engine speed sensor could be the reason behind many issues in your vehicle. It's an essential component of the audi a4 replacement key's transmission because it communicates to the ECU about how fast or slow the car's crankshaft is turning. This sensor could cause the transmission to fail and other components in the car to be affected.

The G5 engine sensor is located at the edge of transmission, above the flywheel ring. It sends signals via an uncolored wire to the ECU pin T55/49. The ECU uses this signal to regulate the amount of fuel and boost, as well as timig. It also transmits it to the G5 Tachometer inside the instrument cluster. You can determine if the sensor is in failure by examining the continuity from the sensor to the tachometer. Additionally, you can 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. You should see around 1000 ohms of resistance between those points. This is a typical component across the Audi 80, 100, 200, UrS and RS2 range from 1985 MC until the 1997 UrS AAN and 1995 RS2 ADU, so the best ones might be availble in wrecking yards.