4 Dirty Little Secrets About The Audi G28 Industry

How to Replace an replacement audi car key G28 Engine Speed Sensor

In this video, Charles the humble mechanic demonstrates how to replace the G28 engine speed sensor. The sensor is situated on the edge of the transmission above the flywheel ring 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 grey wire is located at the edges of the transmission, just above the flywheel ring. The sensor sends an electrical signal through the grey wire to pin T55/49. The ECU uses this information to regulate boost and fuel. It also sends an indicator to the G5 Tachometer located in the instrument cluster.

The sensor serves as a reference for comparing 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 display an error code P00160 which indicates that the Crank Shaft and Intake Camshaft aren't in sync, possibly indicating the chain stretching or a jump link on the upper chain of timing. However, the code won't appear on its own without additional information from other sensors (G4 and G40).

Testing is a bit challenging as there are two different pins replacement key for audi a4 the connector and they perform different functions but the best method to test it is to measure resistance between the sensor and the ECU. It should read around 1000 ohms when the sensor is in full operation. Look for signs of coolant or oil in the connector bay if you are experiencing problems with this part.

2. Injectors

Yesterday, while accelerating from the highway paytoll at maximum speed I noticed a significant decrease in power. It was like the engine was running out of gas. Or, my injectors weren't firing. I took out the spark plugs this morning and found that 3 were drenched in gasoline and the 4th was dry. I put tissue over each injector hole, and when i start the engine without sparks, the three with gazoline jump right out. The 4th one stays shut. I tried to test the ground connections of ECU pins 14,30, and 48/55. I got 0ohm. Therefore, i think the issue is elsewhere.

I also tried to reset the PID but without success. The car will start when the G28 is disconnected, but it is running fine with the G28 plugged in. However the intermittent misfire issue still occurs at higher RPM. The coolant sensor (G62) even when it is unplugged, shows an ice 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 rev the engine.

I don't know what to do. I think I've eliminated everything else. But i am afraid I may have missed something. Let me know should you have any suggestions! TIA!

3. Fuel Pump

The fuel pump in the g28 gets a signal from the RPM sensor. The GM-style transmitter is the same as the G4 and they both work in the 80, 100, 200, UrS and RS2 cars so you can easily find one at a junkyard or from a parts store. Testing them is easy by putting your DMM in resistance mode and measure the resistance between pins 1 (with the bump on the connector's end up) and 2 (2nd from left on the black connector's end). They should be infinite Ohms.

4. ECU

The ECU of our 20vt turbo (3B AAN ABY) engines needs to know both the position and speed the crankshaft to determine timing of fuel injectors, etc. It utilizes a Crank Position Sensor G4 and an Engine Speed Sensor G28 to achieve this. If you are experiencing issues with either of these sensors, the diagnostic scanner will display the codes that could trigger an engine shut down.

Some of the symptoms of a failing G28 sensor include an inaccurate gearbox rev counter, gears shifting quicker than normal and/or misfiring when in gear. It is likely that your sensor is failing and needs to be replaced if you encounter any of these signs. The good news is they are quite affordable and easy to find, especially if you're looking at a Bosch model, which is what we have. Alternatively, GM's version of this component is a good option.

5. Tachometer

A damaged engine sensor could cause a number of problems in your car. It's a crucial component of the transmission of your audi car key holder, as it transmits information to the ECU about how fast or slowly the engine is turning. This sensor can cause the transmission to malfunction and other components of the car to be affected.

The G5 engine speed sensor is located on the outside of the transmission just above the flywheel ring gear and sends a signal directly to the ECU at pin T55/49, via a grey wire. The ECU is then able to process the signal to control fuel, timig, and boost and then sends it on to the G5 Tachometer located in the instrument cluster. You can test the sensor for failure by checking continuity between it and the tachometer, between ECU pin T55/49 and the instrument cluster connection via pin T6a/1 (trace [79]) and between T6a/1 and the instrument cluster pin T26a/12. You should detect an average resistance of 1000 ohms between these points. This is a typical component across the audi a3 keys 80, 100, key audi 200, UrS and RS2 range from 1985 MC until the 1997 UrS AAN and 1995 RS2 ADU, so the best parts could be found in wrecking yards.