How to Replace an audi key replacement cost uk G28 Engine Speed Sensor

In this video Charles the Humble Mechanic shows 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 via an uncolored wire (T55/49) which is then sent to the tachometer located in the instrument cluster.

1. Engine Speed Sensor

It is located on the outside of the transmission just above the flywheel ring gear, the G28 Engine Speed Sensor sends an electrical signal to ECU pin T55/49 via a grey wire. The ECU utilizes this information to control the amount of fuel and boost. It also sends signals to the G5 tachometer inside the instrument cluster.

The sensor is used as a reference for comparing with the G40 Camshaft Position Sensor. The ecu must know when the crankshaft has reached TDC and also where the camshaft lies in order to activate the spark and injectors.

If this sensor fails the ECU will throw a P00160 code which means the Crank Shaft and Intake Camshaft are out of sync, possibly indicating chain stretch or a jumped 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 because there are two pins for the connector and they serve different purposes but the most effective method of testing it is to measure the resistance between the sensor and the ECU. It should read around 1000 ohms when the sensor is at full operation. If you're having issues with this component, look for evidence of coolant or oil in the connector bay.

2. Injectors

Yesterday, when accelerating from highway paytoll at a high speed I noticed a massive reduction in power. It was like the engine was running out of gas. Or my injectors were not firing. I pulled out the spark plugs this morning and found that 3 were soaked with gasoline and the fourth was unclean. When I crank the engine with no sparks, I put a piece of tissue on top of each injector hole and the 3 drenched with gazoline leap out, however the 4th one stays closed. I checked the ground connection on ECU pins 14/55, 30/55 and 48/55. I get 0ohm. Therefore, i think the issue 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 connected. However the intermittent misfire issue persists at higher RPM. The coolant temperature sensor (G62) shows the wrong temp value that is -49c even after unplugging it. I also noticed that the oil gauge in the cockpit shows 2 bar but the actual pressure is zero.

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

3. Fuel Pump

The fuel pump in the g28 is activated by a signal sent by the RPM sensor. The GM-style transmitter is similar to the G4 sender and works on the 80,100,200, UrS, and RS2 vehicles. You can easily find the spare in a salvage shop or parts store. Testing them is easy to do - just put your DMM in resistance mode and measure between pins 1 (with the bump on the connector's end up) and 2 (2nd from the left on the black connector's side). They must be infinite Ohms.

4. ECU

Our 20vt turbo (3B, AAN, ABY and ADU) engines are equipped with an ECU that must know the speed and position of the crankshaft to make decisions regarding timing of the fuel injectors, etc. In order to do this it uses a Crank Position Sensor (G4) and an Engine Speed Sensor Programmers (G28). If either of these sensors go wrong, you will receive codes on the diagnostic scanner that can cause the engine to shut down.

A malfunctioning G28 sensor could result in an inaccurate speed counter replacement key for audi a3 your gearbox and a gearbox which shifts faster than normal, and/or an unfire when in the gear. It is probable that the sensor is failing and requires to be replaced if you experience any of these symptoms. The good news is that they are very affordable and easy to find particularly if you're looking at a Bosch unit which is what we have. Alternately, the GM version of this part is also a great option.

5. Tachometer

A failing engine sensor could cause a myriad of issues within your vehicle. It is a crucial part of your audi q3 key's transmission, because it communicates to the ECU about how fast or slow the vehicle's crankshaft is spinning. This sensor could cause the transmission to malfunction and other components of the car to be affected.

The G5 engine sensor is located near the edge of transmission, above the flywheel ring. It transmits an electrical signal through gray wire to ECU pin T55/49. The ECU then uses and processes the signal to control fuel, timig and boost as well as sends it on to the G5 Tachometer located in the instrument cluster. You can test for sensor failure by examining the continuity of the sensor to the tachometer. Also, you can check continuity between pin T55/49 of the ECU and pin T6a/1 of the instrument cluster (trace [79trace [79]) and between pin T6a/1 as well as pin T26a/12. There should be an average resistance of 1000 ohms in these areas. This is a typical part across the audi a1 Key fob 80 100, 200, UrS and RS2 range from 1985 MC to the 1997 UrS AAN and 1995 RS2 ADU so good ones might be availble in wrecking yards.