What Is Audi G28 History Of Audi G28

How to Replace an audi etron Key G28 Engine Speed Sensor

In this video Charles the Humble Mechanic demonstrates how to replace the G28 engine speed sensor. This sensor is situated at the edge of transmission, above the flywheel gear. It transmits a signal the ECU via a grey wire (T55/49) which is then sent to the tachometer 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 through a grey wire. The ECU utilizes this information to regulate boost and fuel. It also sends a signal 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 the location of the camshaft so it can trigger spark and injectors according to the situation.

If this sensor fails, the ECU will throw an error code P00160 which indicates that the Crank Shaft and Intake Camshaft aren't in sync and possibly indicating the chain stretching or a jump link on the upper timing chain. However, the error code won't appear on its own without additional information from other sensors (G4 and G40).

It is a little tricky to test as there are various connector pins, and each has its own functions. The best method for doing this is by measuring the resistance between the ECU and the sensor. It should read approximately 1000 ohms if the sensor is in full operation. If you're having issues with this part, check for signs of coolant or oil in the connector bay.

2. Injectors

Yesterday, while accelerating at full speed from the highway paytoll, I experienced a big cut in power like the engine is out of gas or the injectors are not firing anymore. In the morning, i removed the spark plugs, three were soaked with gazoline and the fourth was dry. I put tissue over each injector hole, and when i start the engine without sparks, the ones with gazoline jump out. The 4th one remains closed. I tested the ground connection of ECU pins 14,30, and 48/55. I found zero ohm. I assume that the problem is somewhere else.

I also tried to reset the PID but with no luck. The car can start when the G28 is not plugged in and is running fine when it is connected but it still has intermittent misfire issues at higher RPM. The coolant temperature sensor (G62) shows the wrong temp value -49c even when i unplug it. I also noticed that the oil gauge in the cockpit shows 2 bars while the actual pressure is zero.

I'm not certain what to do, i think i've pretty much eliminated everything else. However, i'm afraid that I might have missed something. Let me know should you have any suggestions! TIA!

3. Fuel Pump

The fuel pump of the g28 receives a signal from the RPM sensor. The GM-style transmitter is identical to the G4 and both are used in the 80, 100, 200, Audi remote Key UrS and RS2 cars so you can easily find one at a wrecking yard or at a parts store. Testing them is easy - put your DMM in resistance mode and take measurements between pins 1 (with the bump on the connector end up) and 2 (2nd from the left on the black connector's end). They should be infinite ohms.

4. ECU

Our 20vt turbo (3B AAN, ABY and ADU) engines have an ECU that needs to know the position and speed of the crankshaft in order to make a decision about timing of the fuel injectors, etc. It makes use of a Crank Position Sensor G4 and an Engine Speed Sensor G28 to achieve this. If either of these go wrong, you will receive codes on the diagnostic scanner that can lead to engine shutdown.

Some of the signs of a failed G28 sensor include an inaccurate gearbox rev counter and gears that shift faster than normal, and/or a misfire when you are in gear. It is possible that the sensor is failing and needs to be replaced if you experience any of these signs. They're inexpensive and easy to locate particularly in the case of a Bosch unit like ours. You can also choose the GM version of this part is also a great option.

5. Tachometer

A damaged engine sensor could cause a myriad of issues in your car. It's a vital component of your replacement key audi's transmission, because it communicates to the ECU about how the car's crankshaft is turning. This sensor can cause the transmission to malfunction and other components of the car to be affected.

The G5 engine sensor is located near the edge of the transmission, just above the flywheel ring. It transmits an electrical signal through gray wire to ECU pin T55/49. The ECU utilizes this signal to control fuel and boost, as well as timig. It also relays it to the G5 Tachometer in instrument cluster. You can determine if the sensor is in failure by examining the continuity of the sensor to the tachometer. You can also verify continuity between pin T55/49 of the ECU and pin T6a/1 of the instrument cluster (trace [79trace [79]), and between pin T6a/1 as well as pin T26a/12. You should detect an average resistance of 1000 ohms in these areas. This is a common feature across the audi a3 replacement key 80-100-200-RS2 series, starting from the 1985 MC up to the 1997 UrS An and 1995 RS2 Du So, you may find good ones in wrecking yards.