How to Replace an audi replacement key fob G28 Engine Speed Sensor

Charles the Humble Technician shows you how to replace the G28 Engine Speed Sensor. This sensor is located at the top of the transmission, above the flywheel ring gear. It transmits a signal to the ECU via the grey wire (T55/49) and then to the tachometer in the instrument cluster.

1. Engine Speed Sensor

The grey wire is situated on the edge of transmission, directly above the flywheel ring. The sensor sends signals through the grey wire to pin T55/49. The ECU then utilizes this information to regulate the flow of fuel, timig and boost. It also sends signals to the G5 Tachometer located in 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 display a P00160 error code. This means that the Crank Shaft is out of line with the Intake Camshaft. It could also be a sign of an issue with the chain or a jumpy chain link in the upper timing chain. However the code will not appear on its own, without additional information from other sensors (G4 and G40).

Testing is a bit challenging since there are two connector pins, and they perform different functions but the most effective way to test it is to measure resistance between the sensor and the ECU. It should read about 1000 ohms when the sensor is at full operation. If you're experiencing issues with this part, check for evidence of oil or coolant in the connector bay.

2. Injectors

Yesterday, when i was accelerating to the fullest speed from highway paytoll i had an abrupt drop in power like the engine is running out of gas or injectors are not firing anymore. This morning i pull out the spark plugs. Three were drenched in gazoline, the fourth was dry. I put tissue over each injector hole, and when I turn the engine on without sparks, replacement key for audi the 3 with gazoline jump right out. The fourth one remains closed. I tried to test the ground connections of ECU pins 14,30 and 48/55. I found zero ohm. I think the issue is in another location.

I also tried to reset the PID without success. The car will start when the G28 is disconnected, but it runs fine with the G28 plugged in. However, the intermittent misfire problem continues to occur at higher RPM. The temperature sensor for coolant (G62) shows the wrong temperature value of -49c, even if I unplug it. I also 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, i feel i have pretty much ruled out everything else. But i am afraid I might have missed something. Please let me know if you have any ideas! TIA!

3. Fuel Pump

The fuel pump of the g28 receives signals from the RPM sensor. The GM-style sensor is identical to the G4 and both are used in the 80 100 200, UrS and RS2 cars so you can easily find one at a junkyard or from a parts store. It is simple to test them to do - just put your DMM in resistance mode and take measurements between pins 1 (with the bump on the connector's side up) and 2 (2nd from the left on the black end of the connector). They must be infinite ohms.

4. ECU

Our 20vt turbo (3B, AAN, ABY and ADU) engines are equipped with an ECU that needs to be aware of the speed and position of the crankshaft in order 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 goes bad you will get codes on the diagnostic scanner which can lead to engine shutdown.

A failing G28 sensor can cause an inaccurate gearbox speed counter, a gearbox that shifts faster than normal, or a misfire in the gear. It is possible that your sensor is failing and needs to be replaced if you notice any of these symptoms. The good thing is that they are very cheap and easily accessible, especially if you're looking at the Bosch sensor, which is what we have. You can also choose the GM version of this unit is also a great option.

5. Tachometer

A faulty engine speed sensor could be the reason behind many issues with your car. It's a vital component of your Audi key copy's transmission, because it communicates to the ECU about how fast or slow the vehicle's crankshaft is rotating. If the sensor fails, it could cause problems for the transmission and the rest of the audi car key holder's components.

The G5 engine sensor is located near the edge of transmission, above the flywheel ring. It sends signals via an uncolored wire to the ECU pin T55/49. The ECU then uses and processes the signal to control fuel, timig and boost, and also transmitting it to the G5 Tachometer located in the instrument cluster. You can test for sensor failure by examining the continuity of 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 as well as pin T26a/12. You should detect the resistance to be around 1000 ohms between these points. This is a standard part across the audi key replacement cost uk 80, 100 200, UrS and RS2 range from 1985 MC to the 1997 UrS AAN and 1995 RS2 ADU. Good parts could be found in wrecking yards.