How to Replace an audi key replacement G28 Engine Speed Sensor

In this video Charles the Humble Mechanic demonstrates how to replace the G28 engine speed sensor. This sensor is situated at the edge of transmission over the flywheel gear. It transmits a signal to the ECU via a grey wire (T55/49), then to the tachometer within the instrument cluster.

1. Engine Speed Sensor

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

The sensor is used to connect with the G40 Camshaft position Sensor. The ecu must be aware of when the crankshaft has reached TDC, and where the camshaft lies in order to activate the spark and injectors.

If this sensor fails to function, the ECU will display a P00160 error code. This indicates that the Crank Shaft is out of line with the Intake Camshaft. It could also indicate the possibility of a chain stretch or jumped chain link in the upper chain of timing. The code won't show without the additional information provided by other sensors (G4 or G40).

Testing can be a bit difficult because there are two pins for the connector and they have different functions however the best method of testing it is to measure resistance between the sensor and the ECU. When the sensor is fully operational, it should be reading approximately 1000 ohms. If you're experiencing issues with this sensor, look for evidence of oil or coolant in the connector bay.

2. Injectors

Yesterday, as i was accelerating off 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. Today, i pulled out the spark plugs, three were soaked with gazoline and the fourth one was dry. I put a piece of tissue over each injector hole and when i start the engine with no sparks, the three that have gazoline pop right out. The 4th one stays closed. I tested the ground connection on ECU pins 14/55/30/55/48/55/14/55/48/ i get zero ohm. So i assume the problem is in another place.

I also tried to reset the PID without success. The car will start when the G28 is disconnected, but it runs fine with the G28 plugged in. However, the intermittent misfire problem still occurs at higher RPM. The coolant temperature sensor (G62) shows the wrong temperature value of -49c, even if I unplug it. I also noticed that the oil gauge in the cockpit shows 2 bars when the actual pressure is 0.

I'm not sure what to do, but i feel i have pretty much completely ruled out all other possibilities. But i am afraid I may have missed something. If anyone has suggestions, please share them! TIA!

3. Fuel Pump

The fuel pump on the g28 is activated by a signal sent by 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. Test them out by putting your DMM in resistance mode and measure between pins 1 (with the bump on the connector's side up) and 2 (2nd from left on the black connector's side). They should be infinite ohms.

4. ECU

The ECU of our 20vt turbo (3B AAN ABY) engines needs to know the speed and position of the crankshaft in order to make a decision about timing of the fuel injector, etc. To do this, it uses a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If either of these sensors go wrong, you will receive codes on the diagnostic scanner that could cause engine shut down.

A failing G28 sensor could cause an inaccurate speed counter for your gearbox, a gearbox that shifts more quickly than normal, or a misfire while in the gear. It is probable that the sensor is failing and needs to be replaced if you notice any of these symptoms. They're cheap and easy to find particularly when they're an Bosch unit like ours. Alternately, the GM version of this unit is also a great option.

5. Tachometer

A malfunctioning engine speed sensor could be the cause of a slew of problems in your vehicle. It's a vital component of your audi key audi shell; mouse click the next site,'s transmission, as it sends information to the ECU about how fast or slow the vehicle's crankshaft is rotating. When this sensor fails, it will affect the performance of the transmission as well as the rest of the car's components.

The G5 engine sensor is located near the edge of the transmission, over the flywheel ring. It transmits a signal via a gray wire to the ECU pin T55/49. The ECU then processes this signal to control fuel, timig and boost, and also transmitting it to the G5 tachometer in the instrument cluster. You can check the sensor for failure by checking continuity between it and the tachometer, between the ECU pin T55/49 and the instrument cluster connection on pin T6a/1 (trace [79trace [79]) and between T6a/1 and the instrument cluster pin T26a/12. You should see the resistance to be around 1000 ohms in these areas. This is a standard part that is found across the audi a5 key fob 80, 100, 200, UrS and RS2 range from 1985 MC to the 1997 UrS AAN and 1995 RS2 ADU, so the best parts could be found in wrecking yards.