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 at the edge of transmission over the flywheel gear. It transmits a signal the ECU via a grey wire (T55/49) and then to the tachometer within the instrument cluster.
1. Engine Speed Sensor
The grey wire is situated on the edge of transmission, directly above the flywheel ring. This sensor sends signals through the grey wire to pin T55/49. The ECU then utilizes this information to regulate fuel, timig and boost. It also sends an indicator to the G5 Tachometer within the instrument cluster.
The sensor is used to connect with the G40 Camshaft position Sensor. The ecu must know when the crankshaft is TDC and the location of the camshaft so it can activate spark and injectors accordingly.
If this sensor fails, the ECU will show a P00160 code which means the Crank Shaft and Intake Camshaft aren't in 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).
It can be a bit difficult to test as there are several pins on the connector and each one has different functions. The best method for doing this is to measure the resistance between the ECU and the sensor. If the sensor is operational, it should be reading approximately 1000 ohms. If you're experiencing issues with this part, check for evidence of oil or coolant in the connector bay.
2. Injectors
Yesterday, as i was accelerating off the highway paytoll at a high speed I noticed a significant reduction in power. It was as if the engine had run out of gas. Or my injectors weren't firing. I took out the spark plugs this morning, 3 were soaked with gasoline and the 4th was dry. When I start the engine without sparks i put tissue on top of each injector hole and the 3 that were drenched in gazoline pop out, but the 4th stays shut. I checked the ground connection of ECU pins 14,30, and 48/55. I got 0ohm. I think the issue is elsewhere.
I also tried to reset the PID without success. The car will start when the G28 is disconnected, but it is running fine with the G28 connected. However the intermittent misfire issue persists at higher RPM. The coolant sensor (G62), even when it is unplugged, shows a temperature of -49c. I car key replacement audi also noticed that the oil pressure gauge in the cockpit shows 2 bar when the actual pressure is 0.0 when I crank up the engine.
I'm not certain what to do, but i believe that i've eliminated everything website else. But i am afraid i might have missed something. Please let me know should you have any suggestions! TIA!
3. Fuel Pump
The fuel pump on the g28 is activated by a signal by the RPM sensor. The GM-style transmitter is the same as the G4 and both function in the 80 100 more info 200, UrS and RS2 cars so you can easily find one at a salvage yard or at a parts store. Test them out to do - just put your DMM in resistance mode and take measurements between pins 1 (with the bump on the connector end up) and 2 (2nd from the left on the black end of the connector). They must be infinite Ohms.
4. ECU
The ECU of our 20vt get more info turbo (3B AAN ABY ADU) engines must be aware of the position and speed the crankshaft to determine fuel injector timing, etc. It uses a Crank Position Sensor G4 and an Engine Speed Sensor G28 to accomplish this. If you are experiencing issues with either of these, the diagnostic scanner will show the codes that could trigger the engine shutting down.
A malfunctioning G28 sensor could result in an inaccurate speed counter for the gearbox, a gearbox that shifts more quickly than normal, and/or a misfire while in gear. If you are experiencing any of these issues, it is likely that your sensor is failing and needs replacing. The good thing is that they are very cheap and readily available particularly if you're looking at an Bosch unit like ours. Alternatively, the GM version of this unit is also a great option.
5. Tachometer
A faulty engine speed sensor could be a cause for many issues with your car. It is a crucial part of the Audi's transmission because it communicates to the ECU about how fast or slow the car's crankshaft is turning. This sensor could cause the transmission to fail and other components in the car to be affected.
The G5 engine speed sensor is located at the outside of the transmission, above the flywheel ring gear and sends a signal to the ECU at pin T55/49 via an uncolored wire. The ECU utilizes this signal to regulate the amount of fuel and boost, and also to timigrate. It also sends it to the G5 Tachometer in instrument cluster. You can check audi keys the sensor for any failure by checking the continuity between it and the tachometer, between the 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. You should detect a resistance of approximately 1000 ohms between these two points. This is a common feature across the Audi 80-100-200-RS2 range, from the 1985 MC all the way up to the 1997 UrS AN and the 1995 RS2 Du, so you might find them in wrecking yards.