7 Small Changes You Can Make That'll Make A Huge Difference In Your Audi G28 How to Replace an Audi G28 Engine Speed Sensor

Charles the Humble Technician shows you 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 to the ECU through a grey wire T55/49, then to the tachometer located on the instrument cluster.

1. Engine Speed Sensor

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

The sensor is used to correlate the G40 Camshaft position Sensor. The ecu must be aware when the crankshaft is TDC and where the camshaft is so it can start spark and injectors according to the situation.

If this sensor fails the ECU will display the P00160 error, which means the Crank Shaft and Intake Camshaft aren't in sync and possibly indicating chain stretch or a jumped link on the upper chain of timing. However, the error code won't 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 by measuring resistance between the sensor and the ECU. When the sensor is fully operational, it should be reading around 1000 ohms. Check for signs of coolant or oil in the connector bay if you have issues with this component.

2. Injectors

Yesterday, while accelerating at full speed from the highway paytoll, i experienced an abrupt drop in power as if the engine was running out of gas or injectors are not firing anymore. Today, i pulled out the spark plugs, three were drenched in gazoline, the 4th one was dry. I put tissue over each injector hole and when i start the engine with no sparks, the three that have gazoline pop 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'm assuming the issue is in another place.

I also tried to reset the PID with no success. The car can start when the G28 is not plugged in and it runs perfectly when it is connected however it has intermittent misfire issues at higher RPM. The coolant temperature sensor (G62) shows the wrong temp value -49c, even if I unplug it. I also noticed that the oil gauge in the cockpit shows 2 bar but the actual pressure is 0.

I'm not sure what to do. replacement audi car key feel like i've pretty much eliminated everything else. But i am afraid I may have missed something. Let me know if you have any ideas! TIA!

3. Fuel Pump

The fuel pump on the g28 is activated by a signal sent from the RPM sensor. The GM-style transmitter is similar to the G4 sender and works on the 80,100,200, UrS, and RS2 vehicles. You can easily find the spare in a salvage shop or a parts store. It is simple to test them: simply switch your DMM into resistance mode and test the distance between pins 1 and 2 (with the bump at the connector's end facing upwards). They must be infinite ohms.


4. ECU

The ECU in our 20vt turbo (3B AAN ABY) engines needs to be aware of the speed and position of the crankshaft to make decisions regarding timing of the fuel injector, etc. It uses a Crank Position Sensor G4 and an Engine Speed Sensor G28 to achieve this. If you have a problem with either of these, the diagnostic scanner will display codes that could cause an engine shut down.

A malfunctioning G28 sensor could cause an inaccurate speed counter for the gearbox and a gearbox which shifts more quickly than normal, and/or an unfire when in gear. If you experience any of these issues, it is most likely that your sensor is going bad and needs replacing. The good news is they are very affordable and easy to find, especially in the case of a Bosch unit like ours. You can also choose the GM version of this component is also a good option.

5. Tachometer

A malfunctioning engine sensor can cause a myriad of issues within your vehicle. It's an essential component of your Audi's transmission, since it relays information to the ECU about how fast or slow the vehicle's crankshaft is turning. If this sensor fails, it will disrupt the performance of the transmission and the other car's components.

The G5 engine sensor is located at the outskirts of transmission, above the flywheel ring. It transmits signals via a gray wire to the ECU pin T55/49. The ECU utilizes this signal to control fuel and boost, and also to timigrate. It also sends it to the G5 Tachometer in instrument cluster. You can check for sensor failure by examining the continuity from the sensor to the tachometer. Additionally, you can examine the continuity between pins 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. replacement audi key should show approximately 1000 ohms of resistance between these two points. This is the same across the Audi 80-100-200-RS2 model, ranging from the 1985 MC up to the 1997 UrS An and 1995 RS2 DU You may also find them in wrecking yards.