How to Replace an replacement audi a3 key G28 Engine Speed Sensor
Charles the Humble Technician teaches you how to replace the G28 Engine Speed Sensor. This sensor is located at the top of the transmission above the flywheel ring 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
Located on the edge of the transmission, above the flywheel ring gear G28 Engine Speed Sensor sends a signal to ECU pin T55/49 via a grey wire. The ECU uses this information to regulate fuel and boost. It also sends signals to the G5 Tachometer located in the instrument cluster.
The sensor is used to correlate the G40 Camshaft position Sensor. The ecu must be aware of when the crankshaft has reached TDC, and where the camshaft lies so that it can activate the spark and injectors.
If this sensor fails, the ECU will show an error code P00160 which indicates that the Crank Shaft and Intake Camshaft aren’t in sync and possibly indicating the chain is stretched or a jump link on the upper chain of timing. However the code will not appear on its own without additional information from other sensors (G4 and G40).
It is a little tricky to test since there are different pins on the connector, and each has its own functions. The best way to do it is to measure the resistance between the ECU and the sensor. If the sensor is operational, it should read about 1000 ohms. If you’re having issues with this component, look for evidence of coolant or oil in the connector bay.
2. Injectors
Yesterday, as i was accelerating off the highway paytoll at full speed I noticed a significant drop in power. It was like the engine had run out of gas. Or, my injectors were not firing. I took out the spark plugs this morning and found that 3 were soaked with gasoline and the fourth was dry. When I start the engine with no sparks, i place a tissue on the top of each of the injector holes, the 3 drenched with gazoline pop out, but the 4th stay shut. I tested the ground connection on ECU pins 14/55,30/55 and 48/55 I get zero Ohm. I think the issue is somewhere else.
I also tried to reset the PID but with no luck. The audi car keys will start when the G28 is disconnected, but it runs fine with the G28 connected. However, the intermittent misfire problem continues to occur at higher RPM. The temperature sensor for the coolant (G62) shows the wrong temperature of -49c even when i unplug it. Also i 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 certain what to do, i believe that i’ve ruled out everything else. I’m afraid i may have missed something. If anyone has any suggestions, please let me know! TIA!
3. Fuel Pump
The fuel pump in the g28 can be activated by a signal by the RPM sensor. The GM-style transmitter is identical to the G4 and both are used in the 80, 100 200, UrS and RS2 cars which is why you can easily locate one at a junkyard or from a parts store. It is easy to test them: simply switch your DMM into resistance mode and measure the distance between pins 1 and 2 (with the bump at the connector’s end facing up). They should be infinite Ohms.
4. ECU
Our 20vt turbo (3B, AAN, ABY and ADU) engines have an ECU that has to be aware of the speed and position of the crankshaft to make decisions regarding fuel injector timing etc. It uses a Crank Position Sensor G4 and an Engine Speed Sensor G28 to accomplish this. If you have a problem with either of these sensors, the diagnostic scanner will display codes that could cause an engine shutdown.
Some of the signs of a malfunctioning G28 sensor include an inaccurate rev counter for the gearbox the gears are shifting faster than normal and/or a misfire when you’re in gear. If you have any of these issues, it is most likely that your sensor is failing and should be replaced. The good thing is that they are quite affordable and easy to find, especially if you’re looking at an Bosch sensor, which is what ours are. Alternatively, GM’s version of this component is a good option.
5. Tachometer
A failing engine speed sensor could be a cause for many issues in your car. It’s a crucial component of the transmission in your Programming Audi Key because it relays information to the ECU regarding how fast or slow the engine is turning. When this sensor fails, it can cause problems for the transmission, as well as the rest of the car’s components.
The G5 engine sensor is located at the outskirts of the transmission, just above the flywheel ring. It sends a signal via an uncolored wire to the ECU pin T55/49. The ECU uses this signal to control fuel and boost, as well as timig. It also transmits it to the G5 Tachometer located in the instrument cluster. You can determine if the sensor is in failure by checking continuity from the sensor to the tachometer. Additionally, 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 and pin T26a/12. You should see a resistance of approximately 1000 ohms in these areas. This is a typical component across the audi key replacement cost uk 80 100 200, UrS and RS2 range from 1985 MC to the 1997 UrS AAN and 1995 RS2 ADU. Good ones could be available in wrecking yards.
