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 located on the edge of the transmission, above the flywheel ring gear. It sends a message to the ECU through an uncolored wire T55/49, then to the tachometer located on the instrument cluster.
1. Engine Speed Sensor
The grey wire is situated on the outside of the transmission, directly above the flywheel ring. This sensor sends a signal via the grey wire to pin T55/49. The ECU uses this information to regulate boost and fuel. It also sends an alert to the G5 Tachometer located in the instrument cluster.
The sensor serves as a reference point to connect with the G40 Camshaft Position Sensor. The ecu must be aware when the crankshaft is TDC and the location of the camshaft so it can activate spark and injectors in the right way.
If this sensor fails when it fails, the ECU will display a P00160 error code. This means that the Crank Shaft is not in sync with the Intake Camshaft. It could also indicate a chain stretch or a jumped chain link in the upper chain of timing. The code won't appear without the additional information provided by other sensors (G4 or G40).
It is a little tricky to test as there are various pins on the connector, and each has its own functions. The best method for doing this is to measure the resistance between the ECU and the sensor. It should read around 1000 ohms if the sensor is operating at its maximum. Look for signs of coolant, or oil in the connector bay if there are issues with this part.
2. Injectors
Yesterday, when i was accelerating to the fullest speed from highway paytoll, I experienced massive power loss like the engine is running out of gas or injectors aren't firing at all. I pulled out the spark plugs this morning, 3 were soaked with gasoline and the 4th was dry. When I crank the engine with no sparks, I put a piece of tissue on top of each injector hole and the 3 that were drenched in gazoline jump out but the 4th stay closed. I tested the ground connection on ECU pins 14/55/30/55/48/55/14/55/48/ i get 0ohm. Therefore, i think the issue is in another place.
I also tried to reset the PID with no success. The car will start when the G28 is unplugged, and it is running fine with the G28 connected. However the intermittent misfire issue continues to occur at higher RPM. The temperature sensor for the coolant (G62) shows the wrong temperature value of -49c even when i unplug it. I also noticed that the oil gauge in the cockpit shows 2 bar but the actual pressure is 0.
I'm not sure what to do. I believe that I've ruled everything else out. But i am afraid i might have missed something. Please let me know if you have any ideas! TIA!
3. audi a4 key replacement in the g28 receives signals from the RPM sensor. The GM-style sender is the same as the G4 and both function in the 80 100 200, UrS and RS2 cars which is why you can easily locate one at a wrecking yard or in a local parts store. It is easy to test them - just switch 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 must be infinite Ohms.
4. ECU
The ECU in our 20vt turbo (3B AAN ABY) engines needs to know the position and speed of the crankshaft in order to make a decision about timing of fuel injectors, etc. It makes use of 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 display codes that could cause an engine shut down.
A damaged G28 sensor could cause an inaccurate gearbox speed counter and a gearbox which shifts more quickly than normal, and/or an unfire when in gear. If you are experiencing any of these problems, it is likely your sensor is failing and requires replacement. audi a4 key replacement are cheap and easy-to-find especially if they're a Bosch unit like ours. Alternatively, GM' audi a4 key replacement of this part would be an excellent choice.
5. Tachometer
A malfunctioning engine sensor can cause a variety of issues within your vehicle. It's a vital component of the Audi's transmission because it communicates to the ECU about how fast or slow the car's crankshaft is spinning. If this sensor fails, it will affect the performance of the transmission as well as the other car's components.
The G5 engine speed sensor is located on the edge of the transmission above the flywheel ring gear and sends a signal to the ECU at pin T55/49 through an uncolored wire. The ECU then processes this signal to regulate fuel, timig, and boost and then sends it on to the G5 Tachometer located in the instrument cluster. You can check for sensor 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 [79trace [79]), and between pin T6a/1 and pin T26a/12. You should see an average resistance of 1000 ohms between these two points. This is a common feature across the Audi 80-100-200-RS2 series, starting from the 1985 MC all the way up to the 1997 UrS An and 1995 RS2 DU You may also find them in wrecking yards.