Why Nobody Cares About Audi G28

How to Replace an audi a1 car key G28 Engine Speed Sensor

In this video Charles the humble mechanic demonstrates how to replace the G28 engine speed sensor. This sensor is located near the transmission's edge, above the flywheel gear. It transmits a signal to the ECU via an uncolored wire (T55/49), then to the tachometer within the instrument cluster.

1. Engine Speed Sensor

Located on the edge of the transmission, above the flywheel ring gear G28 Engine Speed Sensor sends an electrical signal to ECU pin T55/49 via the grey wire. The ECU utilizes this information to regulate boost and fuel. It also sends an alert to the G5 Tachometer located in the instrument cluster.

The sensor is used as a reference point to connect with the G40 Camshaft Position Sensor. The ecu must be aware when the crankshaft is TDC and where the camshaft is located so that it can trigger spark and injectors accordingly.

If this sensor fails, the ECU will display an error code P00160. This indicates that the Crank Shaft is out of sync with the Intake Camshaft. It could also indicate a chain stretch or a jump in the chain link of the upper chain of timing. The code will not appear without the additional information provided by other sensors (G4 or G40).

Testing is a bit challenging since there are two connector pins, and they serve different purposes but the most effective way to test it is to measure the resistance between the sensor and the ECU. If the sensor is functional, it should read about 1000 ohms. Look for signs of coolant, or oil in the connector bay if there are issues with this part.

2. Injectors

Yesterday, as i was accelerating off the highway paytoll at full speed I noticed a significant reduction in power. It was as if the engine was running out of gas. Or, my injectors weren't firing. Today, i pulled out the spark plugs. Three were soaked with gazoline and the fourth was dry. I placed a tissue over each hole in the injector and when i turn the engine on without sparks, the 3 with gazoline jump right out. The 4th one remains shut. I tested the ground connection of ECU pins 14,30 and 48/55. I found zero ohm. I think the issue is elsewhere.

I also tried to reset PID but without success. The car can start if the G28 is unplugged and runs fine when it is plugged in, but still has intermittent misfire issues at higher RPM. The temperature sensor for the coolant (G62) shows the wrong temp value -49c, even if I unplug it. I also noticed that the gauge for oil pressure in the cockpit is showing 2 bar while the actual pressure is 0.0 when i rev the engine.

I'm not sure what to do. I think I've ruled everything else out. However, i'm afraid that I might have missed something. If anyone has any ideas please share them! 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 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. It is easy to test them - just switch your DMM into resistance mode and test the distance between pins 1 and 2 (with the bump at the connector end facing up). They should be infinite Ohms.

4. ECU

Our 20vt turbo (3B, AAN, ABY and ADU) engines have an ECU that needs to be aware of the speed and position of the crankshaft to make decisions about fuel injector timing etc. To do this, it makes use of a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If either of these sensors go badly, you will see codes on the diagnostic scanner which could cause engine shut down.

A failing G28 sensor can cause an inaccurate speed counter replacement key for audi the gearbox or a gearbox that shifts more quickly than normal, or a misfire in gear. It is probable that the sensor is failing and needs to be replaced if you experience any of these signs. They are cheap and easy-to-find 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 the cause of many problems in your car. It's an essential component of your audi key programming's transmission, as it sends information to the ECU about how the car's crankshaft is turning. If the sensor fails, it will disrupt the performance of the transmission, as well as the other car's components.

The G5 engine sensor is located near the edge of the transmission, just above the flywheel ring. It sends signals via an uncolored wire to the ECU pin T55/49. The ECU then uses and processes this signal to regulate fuel, timig and boost as well as sends it on to the G5 Tachometer located in the instrument cluster. You can check the sensor for failure by checking continuity between it and the tachometer, between ECU pin T55/49 and the instrument cluster connection on pin T6a/1 (trace [79trace [79]) as well as between T6a/1, and the instrument cluster pin T26a/12. You should observe approximately 1000 ohms of resistance between those two pins. This is a standard part that is found across the audi replacement key service near me 80, 100 200, UrS and RS2 range from 1985 MC to the 1997 UrS AAN and 1995 RS2 ADU so good ones might be availble in wrecking yards.