The Ultimate Cheat Sheet For Audi G28

How to Replace an audi key G28 Engine Speed Sensor

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

1. Engine Speed Sensor

It is located on the outside of the transmission just above the flywheel ring gear G28 Engine Speed Sensor sends signals to ECU pin T55/49 using an uncolored wire. The ECU then uses this information to control the flow of fuel, timig and boost. It also sends an indication 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 when the crankshaft is TDC and where the camshaft is located so that it can start spark and injectors accordingly.

If this sensor fails when it fails, the ECU will display a P00160 error message. This indicates that the Crank Shaft is out of sync with the Intake Camshaft. It could also be a sign of the possibility of a chain stretch or jump in the chain link of the upper chain. However, the code won't appear on its own without additional information from other sensors (G4 and G40).

Testing can be a bit difficult as there are two different pins for the connector and they serve different purposes but the most effective method of testing it is to measure resistance between the sensor and the ECU. It should read approximately 1000 ohms when it is at full operation. Look for signs of coolant, or oil in the connector bay if you have problems with this part.

2. Injectors

Yesterday, while accelerating from the highway paytoll at a high speed I noticed a massive drop in power. It was like the engine had run out of gas. Or my injectors weren't firing. I took out the spark plugs this morning and found that 3 were soaked with gasoline and the fourth was dry. I placed a tissue over each injector hole and when I turn the engine on without sparks, the three with gazoline jump right out. The fourth one remains closed. I checked the ground connection on ECU pins 14/55/30/55/48/55/14/55/48/ I get 0ohm. I'm assuming that the issue is in another location.

I also tried to reset the PID without success. The car will start when the G28 is unplugged, and it is running fine with the G28 connected. However the intermittent misfire issue continues to occur at higher RPM. The coolant sensor (G62) even if it is not plugged in, shows temperatures of -49c. I also noticed that the oil gauge in the cockpit shows 2 bars while the actual pressure is zero.

I don't know what to do. I feel like i've pretty much eliminated everything else. But i'm worried that I might have missed something. Please let me know if you have any ideas! TIA!

3. Fuel Pump

The fuel pump in the g28 is activated by a signal by the RPM sensor. The GM-style transmitter is similar to the G4 sender, and both operate on the 80,100,200, UrS, and RS2 vehicles. You can easily locate a spare in a wrecking shop or parts store. It is easy to test them: simply put your DMM into resistance mode and determine the distance between pins 1 and audi a5 key fob 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 must know the speed and position of the crankshaft to make a decision about timing of the fuel injectors, etc. To accomplish this, it utilizes a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If either of these go bad you will get codes on the diagnostic scanner which can cause the engine to shut down.

A damaged G28 sensor can cause an inaccurate speed counter for your gearbox, a gearbox that shifts faster than normal, or an unfire when in the gear. It is possible that your sensor is failing and requires to be replaced if you encounter any of these signs. The good thing is that they are very affordable and easy to find particularly in the case of a Bosch sensor, like ours. If you prefer, GM's version of this component is a good option.

5. Tachometer

A failing engine speed sensor could be the cause of a slew of issues with your vehicle. It's an essential component of the audi replacement car keys's transmission since it relays information to the ECU about how fast or slow the vehicle's crankshaft is rotating. This sensor can cause the transmission to fail and other components in the car to be affected.

The G5 engine sensor is located at the outskirts of the transmission, over the flywheel ring. It transmits signals via an uncolored wire to the ECU pin T55/49. The ECU utilizes this signal to regulate the amount of fuel and boost, as well as timig. It also transmits it to the G5 Tachometer inside the instrument cluster. You can check for sensor failure by examining the continuity from the sensor to the tachometer. You can also check continuity between pin T55/49 of the ECU and pin T6a/1 of the instrument cluster (trace [79]), and between pin T6a/1 and pin T26a/12. There should be the resistance to be around 1000 ohms between these two points. This is a common component across the audi q3 key 80, 100, 200, UrS and RS2 range from 1985 MC through the 1997 UrS AAN and 1995 RS2 ADU, so the best ones might be availble in wrecking yards.