Why No One Cares About Audi G28

How to Replace an replacement key 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 at the edge of transmission over the flywheel gear. It transmits a signal the ECU via the grey wire (T55/49) and then to the tachometer within the instrument cluster.

1. Engine Speed Sensor

The grey wire is located on the outside of the transmission, just above the flywheel ring. The sensor transmits signals through the grey wire to pin T55/49. The ECU then uses this information to control fuel, timig and boost. It also sends an indicator to the G5 Tachometer in instrument cluster.

The sensor is used as a reference for comparing with the G40 Camshaft Position Sensor. The ecu has to know 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 throw a P00160 code which means the Crank Shaft and Intake Camshaft are not in sync, possibly indicating the chain stretching or a jump link on the upper chain of timing. The code won't show without the additional information provided by other sensors (G4 or G40).

Testing is a bit challenging because there are two connector pins and they serve different purposes however the best method to test it is by measuring resistance between the sensor and the ECU. It should read approximately 1000 ohms when it is at full operation. Look for evidence of coolant or oil in the connector bay if you have issues with this component.

2. Injectors

Yesterday, when accelerating from highway paytoll at maximum speed I noticed a massive decrease in power. It was like the engine was running out cost of audi key replacement gas. Or, my injectors were not firing. I pulled out the spark plugs this morning, 3 were soaked with gasoline and replaced the fourth was unclean. I placed a tissue over each hole in the injector and when i start the engine without sparks, the ones with gazoline jump out. The fourth one remains closed. I tried to test the ground connections of ECU pins 14,30 and 48/55. I found zero ohm. I'm assuming the issue is elsewhere.

I also tried to reset the PID but with no luck. The car will start when the G28 is unplugged, and it works fine when the G28 connected. However the intermittent misfire issue continues to occur at higher RPM. The coolant sensor (G62), even when unplugged, still shows a temperature of -49c. I also noticed that the gauge for oil pressure in the cockpit is showing 2 bar when the actual pressure is 0.0 when I crank up the engine.

I'm not sure what to do. I think I've all other possibilities out. But i'm worried that i might have missed something. Let me know If you have any suggestions! TIA!

3. Fuel Pump

The fuel pump in the g28 receives a signal from the RPM sensor. The GM-style transmitter is identical to the G4 sender, and both operate on the 80,100,200, UrS, and RS2 vehicles. You can easily find a spare in a wrecking shop or parts store. It is easy to test them - just 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 requires to know both the position and speed the crankshaft to determine timing of the fuel injector, etc. To accomplish this, audi a5 key fob (read this) it makes use of a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If either of these sensors go badly, you will see codes on the diagnostic scanner which could cause engine shut down.

The signs of a failing G28 sensor are an inaccurate rev counter in the gearbox and gears that shift faster than normal, and/or a misfire when you're in gear. It is possible that the sensor is failing and needs to be replaced if you experience any of these symptoms. They're inexpensive and easy to locate particularly if they're a Bosch model like ours. Alternatively, the GM version of this component is also a good option.

5. Tachometer

A faulty engine speed sensor could be a cause for a slew of issues in your vehicle. It's an essential component of your audi replacement key service's transmission, since it relays information to the ECU about how fast or slow the vehicle's crankshaft is turning. When this sensor fails, it will disrupt the performance of the transmission and the other car's components.

The G5 engine speed sensor is situated on the edge of the transmission, above the flywheel ring gear. It transmits a signal to the ECU at pin T55/49 through an uncolored wire. The ECU utilizes this signal to control the flow of fuel and boost as well as timig. It also relays it to the G5 Tachometer in instrument cluster. You can determine if the sensor is in failure by examining the continuity of the sensor to the tachometer. Additionally, you can verify continuity between pin T55/49 of the ECU and pin T6a/1 of the instrument cluster (trace [79trace [79]) and between pin T6a/1 and pin T26a/12. You should detect a resistance of approximately 1000 ohms between these two points. This is the same across the audi smart Key Replacement 80-100-200-RS2 range, from the 1985 MC all the way up to the 1997 UrS An and 1995 RS2 DU, so you might find some good ones in wrecking yards.