How to Replace an Audi G28 Engine Speed Sensor
In this video, Charles the humble mechanic demonstrates how to replace the G28 engine speed sensor. This sensor is situated near the transmission's edge, above the flywheel gear. It transmits a signal to the ECU via an uncolored 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 the G28 Engine Speed Sensor sends an electrical signal to ECU pin T55/49 through the grey wire. The ECU utilizes this information to regulate fuel and boost. It also sends an indication to the G5 Tachometer located in the instrument cluster.
The sensor is used to connect the G40 Camshaft position Sensor. The ecu needs to know when the crankshaft reached TDC, and the position of the camshaft, to trigger the spark and injectors.
If this sensor fails, the ECU will display a P00160 error message. This means that the Crank Shaft is out of alignment with the Intake Camshaft. It could also be a sign of a chain stretch or a jumped chain link in the upper timing chain. However the code will not appear on its own without additional information from other sensors (G4 and G40).
Testing is a bit challenging as there are two different connector pins, and they serve different purposes however the best method of testing it is to measure the resistance between the sensor and the ECU. It should read approximately 1000 ohms when the sensor is operating at its maximum. If you're having issues with this part, check for signs of coolant or oil in the connector bay.
2. Injectors
Yesterday, when i was accelerating to the fullest speed from highway paytoll i had a big cut in power like the engine is out of gas or injectors aren't firing any more. I pulled out the spark plugs this morning and found that 3 were drenched in gasoline and the fourth was dry. I put tissue over each injector hole and when i start the engine without sparks, the ones with gazoline jump out. The 4th one stays shut. I checked the ground connection on ECU pins 14/55,30/55 and 48/55 I get 0ohm. Therefore, i think the issue is somewhere else.
I also tried to reset the PID with no success. The car will start when the G28 is not plugged in and runs fine when it is connected but it still has the intermittent misfire issue at higher RPM. The temperature sensor for the coolant (G62) shows the wrong temperature of that is -49c even after unplugging it. Also i noticed that the oil pressure gauge in the cockpit shows 2 bar while the actual pressure is 0.0 when I crank up the engine.
I don't know what to do. I think I've ruled everything else out. I'm concerned that i may have missed something. If anyone has any suggestions, please let me know! TIA!
3. Fuel Pump
The fuel pump of the g28 receives a signal from the RPM sensor. The GM-style transmitter is the same as the G4 and they both work in the 80, 100, 200, UrS and audi lost key RS2 cars so you can easily find one at a junkyard or in a local parts store. Testing them is easy to do - just put your DMM in resistance mode and measure the resistance between pins 1 (with the bump on the connector's end up) and 2 (2nd from left on the black connector's end). They must be infinite ohms.
4. ECU
Our 20vt turbo (3B AAN, ABY, and ADU) engines have an ECU that needs to know the position and speed of the crankshaft to make decisions read more about fuel injector timing etc. It utilizes a Crank Position Sensor G4 and an Engine Speed Sensor G28 to accomplish this. If either of these go badly, you will see codes on the diagnostic scanner that could cause engine shut down.
A damaged G28 sensor could cause an inaccurate speed lost audi keys counter for audi replacement car keys your gearbox, a gearbox that shifts more quickly than normal, and/or an unfire when in gear. If you experience any of these problems, it is likely your sensor is failing and needs replacing. They're cheap and easy to find, especially when they're a Bosch model like ours. Alternatively, GM's version of this replace audi key component is an option.
5. Tachometer
A failing engine speed sensor could be the cause of a slew of problems in your vehicle. It's an essential component of your Audi's transmission, as it sends information to the ECU about how fast or slow the car's crankshaft is spinning. This sensor could cause the transmission to fail and other components of the car to be affected.
The G5 engine sensor is located at the outskirts of transmission, above the flywheel ring. It transmits an electrical signal through a gray wire to the ECU pin T55/49. The ECU uses this signal to control fuel and boost, and also to timigrate. It also sends it to the G5 Tachometer inside 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 via pin T6a/1 (trace [79trace [79]) and between pin T6a/1 and the instrument cluster pin T26a/12. It should show approximately 1000 ohms resistance between those points. This is a typical part across the Audi 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.