How to Replace an audi advance key 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 just above the flywheel gear. It sends a message to the ECU through a grey wire T55/49, then to the tachometer in the instrument cluster.

1. Engine Speed Sensor

The sensor is located at the edge of the transmission, above the flywheel ring gear the G28 Engine Speed Sensor sends a signal to ECU pin T55/49 using the grey wire. The ECU then utilizes this information to regulate the flow of fuel, timig and boost. It also sends signals to the G5 tachometer in the instrument cluster.

The sensor serves as a reference to correlate with the G40 Camshaft Position Sensor. The ecu must be aware of when the crankshaft has reached TDC and also the location of the camshaft to trigger the spark and injectors.

If this sensor fails, the ECU will display a P00160 error message. This means that the Crank Shaft is not in alignment with the Intake Camshaft. It could also be a sign of an issue with the chain or a jumpy chain link in the upper 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 because there are different pins on the connector and they all have different functions. The most effective method to test it is by measuring the resistance between the ECU and the sensor. When the sensor is fully functional, it should read around 1000 ohms. Look for evidence of coolant or oil in the connector bay if there are problems with this part.

2. Injectors

Yesterday, as i was accelerating off the highway paytoll at full speed, i noticed a huge decrease in power. It was like the engine was running out of gas. Or my injectors weren't firing. This morning i pull out the spark plugs, 3 were drenched in gazoline, the 4th one was dry. I put a piece of tissue over each hole in the injector and when i turn the engine on without sparks, the three that have gazoline pop right out. The 4th one remains closed. I tested the ground connection of ECU pins 14,30, and 48/55. I got zero ohm. Therefore, i think the issue is elsewhere.

I also tried to reset the PID with no success. The car will start when the G28 is disconnected and it runs perfectly when it is plugged in, but still has the intermittent misfire issue at higher RPM. The temperature sensor for the coolant (G62) shows the wrong temperature of -49c even when i unplug it. Also i noticed that the gauge for oil pressure in the cockpit shows 2 bar, whereas the actual pressure is 0.0 when i rev the engine.

I'm not sure what to do, i think i've pretty much ruled out 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 on the g28 is 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 a spare in a wrecking 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 end facing up). They should be infinite Ohms.

4. ECU

The ECU in our 20vt turbo (3B AAN ABY) engines needs to be aware of the position and speed of the crankshaft in order to make a decision about fuel injector timing, etc. To do this, it utilizes a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If you are experiencing issues with either of these, the diagnostic scanner will display codes that could lead to an engine shut down.

The signs of a failing G28 sensor include an inaccurate rev counter in the gearbox and gears that shift faster than normal and/or a misfire when in gear. It is likely that the sensor is failing and requires to be replaced if you notice any of these signs. The good news is they are quite affordable and easily accessible, especially in the case of an Bosch unit which is what ours are. You can also choose the GM version of this component is also a good choice.

5. Tachometer

A malfunctioning engine speed sensor could be the reason behind a slew of issues with your audi car key case. It is a crucial part of the audi tt key fob's transmission as it sends information to the ECU about how fast or slow the replacement car key audi's crankshaft is rotating. This sensor could cause the transmission to fail and other components in the car to be affected.

The G5 engine sensor is located near the edge of the transmission, just above the flywheel ring. It sends signals via an uncolored wire to the ECU pin T55/49. The ECU uses this signal to control the amount of fuel and boost, and also timig. It also transmits it to the G5 Tachometer in instrument cluster. You can check for sensor failure by examining the continuity from 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 [79]) and between pin T6a/1 as well as pin T26a/12. There should be the resistance to be around 1000 ohms in these areas. This part is common across the new audi key 80-100-200-RS2 range, from the 1985 MC up to the 1997 UrS An and 1995 RS2 Du You may also find some good ones in wrecking yards.