How to Replace an Audi G28 Engine Speed Sensor

Charles the Humble Technician teaches how to replace the G28 Engine Speed Sensor. This sensor is situated near the transmission's edge just above the flywheel gear. It transmits a signal to the ECU via the grey wire (T55/49) which is then sent to the tachometer within the instrument cluster.

1. Engine Speed Sensor

It is located on the outside of the transmission just above the flywheel ring gear, the G28 Engine Speed Sensor sends signals to ECU pin T55/49 via an uncolored wire. The ECU uses this information to regulate the amount of fuel and boost. It also sends a signal to the G5 tachometer inside the instrument cluster.

The sensor is used to link with the G40 Camshaft position Sensor. The ecu must be aware when the crankshaft is TDC and where the camshaft is so it can trigger spark and injectors in the right way.

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

It's a bit tricky to test since there are various pins on the connector and each has its own functions. The best way to do it is by measuring the resistance between the ECU and the sensor. It should read around 1000 ohms if the sensor is at full operation. Check for signs of coolant, or oil in the connector bay if you have issues with this part.

2. Injectors

Yesterday accelerating full speed from highway paytoll, I experienced an abrupt drop in power as if the engine was running out of gas or the injectors aren't firing at all. Today, i pulled out the spark plugs, three were soaked with gazoline and the 4th one was dry. I placed a tissue over each injector hole, and when i turn the engine on without sparks, the 3 that have gazoline pop right out. The fourth one remains closed. I checked the ground connection on ECU pins 14/55, 30/55 and 48/55. I got zero ohm. I think the issue is in another location.

I also tried to reset PID without success. The car can start when the G28 is unplugged and runs fine when it is connected, but still is experiencing intermittent misfires at higher RPM. The coolant sensor (G62), even when unplugged, still shows an ice temperature of -49c. I also noticed that the oil gauge in the cockpit shows 2 bars but the actual pressure is zero.

I'm not sure what to do, as i believe that i've eliminated everything else. I'm concerned that i may have missed something. If anyone has any suggestions, please chime in! TIA!

3. Fuel Pump

The fuel pump of the g28 receives signals 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 find an extra in a wrecking shop or a parts store. It is simple to test them - just switch your DMM into resistance mode and measure the distance between pins 1 and 2 (with the bump at the connector's end facing up). They must be infinite Ohms.

4. ECU

Our 20vt turbo (3B, AAN, ABY and ADU) engines have an ECU that has to be aware of the speed and position of the crankshaft to make decisions regarding timing of the fuel injectors, etc. It makes use of a Crank Position Sensor G4 and an Engine Speed Sensor G28 to accomplish this. If you encounter a problem with either of these sensors, the diagnostic scanner will show codes that could lead to an engine shut down.

The signs of a failing G28 sensor include an inaccurate rev counter for the gearbox, gears shifting quicker than normal and/or misfiring when you are in gear. It is likely that the sensor is failing and requires to be replaced if you encounter any of these signs. They're inexpensive and easy to locate particularly when they're an Bosch sensor like ours. If you prefer, GM's version of this component is an excellent choice.

5. Tachometer

A failing engine sensor could cause a myriad of issues in your car. It is a crucial part of the audi replacement key cost's transmission since it relays information to the ECU about how fast or slow the car's crankshaft is spinning. This sensor can cause the transmission to malfunction and other components of the car to be affected.

The G5 engine sensor is located at the edge of the transmission, just above the flywheel ring. It sends a signal via gray wire to ECU pin T55/49. The ECU then uses and processes this signal to control fuel, timig, and boost and then transmitting it to the G5 tachometer in the instrument cluster. You can test the sensor for failure by examining the continuity between it and the tachometer. You can also check continuity between ECU pin T55/49 and the instrument cluster connection to pin T6a/1 (trace [79]) and between pin T6a/1 and the instrument cluster pin T26a/12. It should show around 1000 ohms of resistance between those two pins. This part is common across the replacement audi key cost Uk 80-100-200-RS2 model, ranging from the 1985 MC up to the 1997 UrS An and 1995 RS2 Du So, you may find them in wrecking yards.