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 located on the outside of the transmission over the flywheel gear. It transmits a signal the ECU via the grey wire (T55/49) and then to the tachometer within 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 sends a signal via the grey wire to pin T55/49. The ECU utilizes this information to regulate the amount of fuel and boost. 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 the location of the camshaft so it can activate spark and injectors accordingly.

If this sensor fails the ECU will throw the P00160 error, which means the Crank Shaft and Intake Camshaft are not in sync, possibly indicating chain stretch or a jumped link on the upper chain of timing. The code will not appear without the additional information supplied by other sensors (G4 or G40).

Testing can be a bit difficult since there are two connector pins and they have different functions but the most effective method to test it is to measure resistance between the sensor and the ECU. When the sensor is operational, it should read around 1000 ohms. Check for signs of coolant, or oil in the connector bay if there are issues with this component.

2. Injectors

Yesterday, when i was accelerating to the fullest speed from highway paytoll, i experienced a big cut in power like the engine is out of gas or injectors are not firing anymore. This morning i pull out the spark plugs, three were drenched in gazoline, the fourth one was dry. When I crank the engine without sparks, i place a tissue on the top of each of the injector holes and the 3 drenched with gazoline jump out but the 4th stays shut. I checked the ground connection of ECU pins 14,30, and 48/55. I got 0ohm. So i assume the problem is somewhere else.

I also tried to reset the PID but without success. The car will start when the G28 is unplugged, and it is running fine with the G28 connected. However the intermittent misfire issue still occurs at higher RPM. website The coolant sensor (G62) even when unplugged, still shows a temperature of -49c. I also noticed that the oil pressure gauge in the cockpit is showing 2 bar while the actual pressure is 0.0 when I crank up the engine.

I'm not certain what to do, as i feel i have pretty much completely ruled out all other possibilities. However, i'm afraid that I might have missed something. If anyone audi a3 replacement key has any ideas please share them! 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 more info used in the 80, 100, 200, UrS and RS2 cars so you can easily find one at a wrecking yard or in a local parts store. Testing them is easy by putting your DMM in resistance mode and measure the resistance between pins 1 (with the bump on the connector end up) and 2 (2nd from left on the black end of the connector). They should be infinite ohms.

4. ECU

The ECU audi car keys in our 20vt turbo (3B AAN ABY ADU) engines needs to know the position and speed of the crankshaft to make decisions regarding timing of fuel injectors, etc. In order to do this it uses a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If you have a problem with either of these sensors, the diagnostic scanner will display codes that could lead to an engine shutdown.

The signs of a malfunctioning G28 sensor include an inaccurate rev counter for the gearbox and gears that shift read more faster than normal, and/or a misfire when in gear. It is possible that your sensor is failing and needs to be replaced if you encounter any of these symptoms. They are cheap and easy-to-find particularly if they're a Bosch model like ours. If you prefer, GM's version of this part would be an option.

5. Tachometer

A malfunctioning engine sensor can cause a myriad of issues within your vehicle. It's an essential component of the transmission of your Audi since it sends information to the ECU on how fast or slowly the car's engine is turning. This sensor can cause the transmission to malfunction and other car components to be affected.

The G5 engine sensor is located at the edge of the transmission, over the flywheel ring. It transmits an electrical signal through a gray wire to the ECU pin T55/49. The ECU utilizes this signal to control the amount of fuel and boost, and also to timigrate. It also transmits it 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]) and between T6a/1 and the instrument cluster pin T26a/12. It should show approximately 1000 ohms resistance between these two points. This is a common feature across the Audi 80-100-200-RS2 series, starting beginning with the 1985 MC and up to the 1997 UrS An and 1995 RS2 DU You may also find some good ones in wrecking yards.