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The Most Convincing Evidence That You Need Audi G28
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. The sensor is located on the edge of the transmission above the flywheel ring gear. It sends a signal to the ECU via a grey wire (T55/49), then to the tachometer in the instrument cluster.

1. Engine Speed Sensor

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

The sensor is used to connect the G40 Camshaft position Sensor. The ecu must know when the crankshaft is TDC and where the camshaft is so it can trigger spark and injectors accordingly.

If this sensor fails to function, the ECU will display a P00160 error message. This indicates that the Crank Shaft is not in line with the Intake Camshaft. It could also indicate the possibility of a chain stretch or jumpy chain link in the upper chain. However, the code won't appear on its own without additional information from other sensors (G4 and G40).

Testing is a bit tricky as there are two different connector pins and they have different functions but the most effective method to test it is by measuring resistance between the sensor and the ECU. It should read about 1000 ohms if the sensor is at full operation. If you are having problems with this sensor, look for evidence of coolant or oil in the connector bay.

2. Injectors

Yesterday, when i was accelerating to the fullest speed from highway paytoll i had massive power loss as if the engine was running out of gas or the injectors aren't firing any more. This morning i pull out the spark plugs, 3 were drenched in gazoline, the fourth was dry. When i crank the engine with no sparks, I put a piece of tissue on top of each injector hole and the 3 drenched with gazoline jump out but the 4th stay closed. I tested the ground connection on ECU pins 14/55/30/55/48/55/14/55/48/ I get zero ohm. I think the issue is somewhere else.

I also tried to reset the PID but without success. The car will start when the G28 is unplugged, and it runs fine with the G28 connected. However the intermittent misfire issue continues to occur at higher RPM. The coolant sensor (G62) even if it is not plugged in, shows a temperature of -49c. I also noticed that the gauge for oil pressure in the cockpit shows 2 bar when the actual pressure is 0.0 when I crank up the engine.


I'm not sure what to do. I believe that I've eliminated everything else. I'm worried that i might have missed something. Let me know if you have any ideas! TIA!

3. Fuel Pump

The fuel pump in the g28 can be activated by a signal from the RPM sensor. The GM-style transmitter is identical to the G4 sender and works on the 80,100,200, UrS, and RS2 vehicles. You can easily locate an extra in a wrecking shop or a parts store. Testing audi car key is easy by putting your DMM in resistance mode and measure the resistance between pins 1 (with the bump on the connector's side up) and 2 (2nd from the left on the black connector's side). They should be infinite Ohms.

4. ECU

Our 20vt turbo (3B, AAN, ABY and ADU) engines are equipped with an ECU that has to know the position and speed of the crankshaft to make decisions about timing of the fuel injectors, etc. It utilizes a Crank Position Sensor G4 and an Engine Speed Sensor G28 to achieve this. If either of these goes badly, you will see codes on the diagnostic scanner that can cause the engine to shut down.

A malfunctioning G28 sensor can cause an inaccurate speed counter for the gearbox and a gearbox which shifts faster than normal, or an unfire when in gear. It is possible that your sensor is failing and requires to be replaced if you experience any of these signs. They are cheap and easy-to-find particularly in the case of a Bosch sensor like ours. You can also choose the GM version of this unit is also a great option.

5. Tachometer

A failing engine sensor could cause a variety of issues in your car. It is an important part of the transmission of your Audi, as it transmits information to the ECU regarding how fast or slow the engine is spinning. This sensor could cause the transmission to fail and other components in the car to be affected.

The G5 engine speed sensor is located at the outside of the transmission, above the flywheel ring gear. It sends a signal to the ECU at pin T55/49 through an uncolored wire. The ECU then uses and processes this signal to regulate fuel, timig and boost, and also sends it on to the G5 tachometer inside the instrument cluster. You can determine if the sensor is in failure by examining the continuity of the sensor to the tachometer. Additionally, 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 and pin T26a/12. You should see the resistance to be around 1000 ohms in these areas. This part is common 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, so you might find some good ones in wrecking yards.

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