How to Replace an Audi G28 Engine Speed Sensor
In this video, Charles the Humble Mechanic shows how to replace the G28 engine speed sensor. The sensor is located near the edges of the transmission just above the flywheel ring gear. It transmits a signal the ECU via an uncolored wire (T55/49) and then to the tachometer within the instrument cluster.
1. Engine Speed Sensor
It is located on the outside of the transmission above the flywheel ring gear G28 Engine Speed Sensor sends an electrical signal to ECU pin T55/49 using an uncolored wire. The ECU then utilizes this information to regulate the boost, fuel, and timig. It also sends signals to the G5 Tachometer located in the instrument cluster.
The sensor serves as a reference for comparing with the G40 Camshaft Position Sensor. The ecu needs to know when the crankshaft is TDC and where the camshaft is located so that it can activate spark and injectors accordingly.
If this sensor fails, the ECU will display an error code P00160 which indicates that the Crank Shaft and Intake Camshaft are not in sync and possibly indicating chain stretch or a jumped link on the upper timing chain. The code won't show without the additional information supplied by other sensors (G4 or G40).
Testing is a bit challenging since there are two pins for the connector and they perform different functions however the best way to test it is by measuring resistance between the sensor and the ECU. It should read about 1000 ohms when the sensor is in full operation. Look for signs of coolant or oil in the connector bay if there are problems with this part.
2. Injectors
Yesterday, as i was accelerating off the highway paytoll at maximum speed, i noticed a huge drop in power. It was as if the engine had run out of gas. Or my injectors were not firing. This morning i pull out the spark plugs. Three were drenched with gazoline the 4th one was dry. I put tissue over each hole in the injector and when i start the engine without sparks, the three with gazoline jump out. The 4th one stays shut. I inspected the ground connection on ECU pins 14/55,30/55 and 48/55 i get 0ohm. So i assume the problem is in another place.
I also tried to reset PID but without success. The car will start if the G28 is disconnected and it runs perfectly when it is connected website however it has intermittent misfire issues at higher RPM. The temperature sensor for coolant (G62) shows the wrong temp value -49c even when i unplug it. I also noticed that the oil pressure gauge in the cockpit shows 2 bar when the actual pressure is 0.0 if i crank up the engine.
I'm not sure what to do, as i believe that i've eliminated everything else. But i am afraid i might have missed something. Let me know should you have any suggestions! TIA!
3. Fuel Pump
The fuel pump in the g28 is activated by a signal sent by the RPM sensor. audi replacement key uk The GM-style audi key programming near me sensor is identical to the G4 and both are used in the 80, 100, 200, UrS and RS2 cars so you can easily find one at a junkyard or from a parts store. It is simple 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 end facing upwards). They should be infinite Ohms.
4. ECU
Our 20vt turbo (3B, AAN, ABY and ADU) engines have an ECU that has to know the speed and position of the crankshaft to make decisions about timing of the fuel injectors, etc. It uses a Crank Position Sensor G4 and an Engine Speed Sensor G28 to achieve this. If either of these sensors go wrong, you will receive codes on the diagnostic scanner that can cause the engine to shut down.
A failing G28 sensor could result in an inaccurate gearbox speed counter or a gearbox that shifts faster than normal, and/or a misfire while in gear. If you are experiencing any of these replacement key for audi a4 problems, it is likely that your sensor is deteriorating and requires replacement. The good news is they are quite affordable and easily accessible particularly in the case of an Bosch model, which is what we have. Alternately, GM's version this part would be an option.
5. Tachometer
A malfunctioning engine sensor can cause a number of problems in your car. It is a crucial part of your Audi's transmission, as it sends information to the ECU about how fast or slow the car's crankshaft is spinning. If this sensor fails, it can cause problems for the transmission as well as the other car's components.
The G5 engine sensor is located near the edge of transmission, above the flywheel ring. It sends signals via a gray wire to the ECU pin T55/49. The ECU utilizes this signal to control the flow of fuel more info and boost and also timig. It also relays it to the G5 Tachometer in instrument cluster. You can check the sensor for any failure by checking the continuity between it and the tachometer, between ECU pin T55/49 and the instrument cluster connection to pin T6a/1 (trace [79trace [79]) as well as between T6a/1, and the instrument cluster pin T26a/12. It should show approximately 1000 ohms resistance between those two pins. This is a common component across the Audi 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.