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 just above the flywheel gear. It transmits a signal to the ECU via a grey wire T55/49, then to the tachometer on the instrument cluster.
1. Engine Speed Sensor
Located on the edge of the transmission above the flywheel ring gear the G28 Engine Speed Sensor sends a signal to ECU pin T55/49 via an uncolored wire. The ECU then uses this information to control the boost, fuel, and timig. It also sends an alert to the G5 Tachometer within the instrument cluster.
The sensor is used to correlate with the G40 Camshaft position Sensor. The ecu must know when the crankshaft has reached TDC and also the position of the camshaft, to trigger the spark and injectors.
If this sensor fails to function, the ECU will display a P00160 error code. This indicates that the Crank Shaft is out of sync with the Intake Camshaft. It could also be a sign of the possibility of a chain stretch or jumped chain link in the upper chain. The code won't appear without the additional information supplied by other sensors (G4 or G40).
It can be a bit difficult to test since there are various pins on the connector and they all have different functions. The best method for doing this is by measuring the resistance between the ECU and the sensor. It should read approximately 1000 ohms when it is operating at its maximum. If you're having issues with this part, check for evidence of oil or coolant in the connector bay.
2. Injectors
Yesterday, when i was accelerating to the fullest speed from highway paytoll, i experienced an abrupt drop in power like the engine is running out of gas or the injectors aren't firing any more. In the morning, i removed the spark plugs. Three were drenched with gazoline the fourth was dry. I put a piece of 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 tested the ground connection of ECU pins 14,30, and 48/55. I found zero ohm. I'm assuming that the issue is somewhere else.
I also tried to reset the PID but without success. The car will start when the G28 is disconnected, but it runs fine with the G28 connected. However the intermittent misfire issue continues to occur at higher RPM. The coolant sensor (G62), even when unplugged, still shows an ice temperature of -49c. I also noticed that the oil gauge in the cockpit shows website 2 bars but the actual pressure is 0.
I don't know what to do. I feel like i've pretty much all other possibilities out. I'm worried that i might have missed something. If anyone has any ideas please let me know! TIA!
3. Fuel Pump
The fuel pump on the g28 is activated by a signal sent by the RPM sensor. The GM-style transmitter functions similarly to the G4 sender and both work audi a3 replacement key on the 80,100,200, UrS, and RS2 vehicles. You can easily find an extra in a wrecking shop or a parts store. It is easy to test them: simply put your DMM into resistance mode and determine the distance between pins 1 and 2 (with the bump at the connector's end facing up). They should be infinite Ohms.
4. ECU
The ECU in our 20vt turbo (3B AAN ABY ADU) engines must know both the speed and position of the crankshaft in order to make a decision about fuel injector timing, etc. In order to do this it makes use of a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If either of these sensors go bad you will get codes on the diagnostic scanner which could cause engine shut down.
A failing G28 sensor can cause an inaccurate gearbox speed audi car keys counter and a gearbox which shifts more quickly than normal, or an unfire when in gear. It is probable that your sensor is failing and requires to be replaced if you notice any of these symptoms. They're inexpensive and easy to locate especially when they're a Bosch sensor like ours. If you prefer, GM's version of this part would be a good option.
5. Tachometer
A malfunctioning engine sensor can cause a variety of issues in your car. It's a vital component of your Audi's transmission, as it sends information to the ECU about how fast or slow the vehicle's crankshaft is rotating. If the sensor fails, it could disrupt the performance of the transmission, as well as the other car's components.
The G5 engine speed sensor is located on the outside of the transmission, above the flywheel ring gear. here It sends a signal directly to the ECU at pin T55/49 via an uncolored wire. The ECU then processes this signal to regulate fuel, timig and boost and then transmitting it to the G5 tachometer in the instrument cluster. You can determine if the sensor is in failure by examining the continuity of 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 [79]) and between pin T6a/1 as well as pin T26a/12. There should be an average resistance of 1000 ohms between these points. This is the same across the Audi 80-100-200-RS2 model, ranging beginning with the 1985 MC and up to the 1997 audi tt keys UrS AN and the 1995 RS2 Du You may also find them in wrecking yards.