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. The sensor is located near the edges of the transmission just above the flywheel ring gear. It transmits a signal to the ECU via a grey wire T55/49, then to the tachometer located on the instrument cluster.
1. Engine Speed Sensor
The grey wire is situated on the edge of transmission, above the flywheel ring. The sensor transmits a signal via the grey wire to pin T55/49. audi a4 key replacement utilizes this information to regulate the flow of fuel, timig and boost. It also sends signals to the G5 tachometer inside the instrument cluster.
The sensor serves as a reference point to connect with the G40 Camshaft Position Sensor. they said has to know when the crankshaft reached TDC, and the position of the camshaft, in order to activate 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 alignment with the Intake Camshaft. It could also indicate an issue with the chain or a jumped chain link in the upper chain. The code will not appear without the additional information provided by other sensors (G4 or G40).
Testing can be a bit difficult since there are two connector pins, and they have different functions but the most effective method of testing it is to measure resistance between the sensor and the ECU. It should read approximately 1000 ohms when it is at full operation. Look for Suggested Webpage of coolant or oil in the connector bay if you have issues with this part.
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 at all. Today, i pulled out the spark plugs, 3 were drenched with gazoline the 4th one was dry. I put tissue over each injector hole and when I turn the engine on without sparks, the 3 with gazoline jump out. The 4th one remains shut. I tried to test the ground connections of ECU pins 14,30, and 48/55. I got 0ohm. I'm assuming the issue is elsewhere.
I also tried to reset PID but without success. The car will start when the G28 is disconnected, but it is running fine with the G28 plugged in. However the intermittent misfire issue continues to occur at higher RPM. The temperature sensor for the coolant (G62) shows the wrong temp value -49c even when i unplug it. I also noticed that the oil gauge in the cockpit shows 2 bars while the actual pressure is 0.
I'm not certain what to do, as i believe that i've completely ruled out all other possibilities. But i'm worried that i might have missed something. Let me know if you have any ideas! TIA!
3. Fuel Pump
The fuel pump in the g28 is activated by a signal sent by the RPM sensor. The GM-style transmitter is identical to the G4 sender, and both operate on the 80,100,200, UrS, and RS2 vehicles. You can easily find the spare in a salvage shop or 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 on the connector's edge facing up). They must be infinite Ohms.
4. ECU
The ECU of our 20vt turbo (3B AAN ABY) engines needs to know both the position and speed the crankshaft in order to make a decision about timing of the fuel injector, etc. It utilizes a Crank Position Sensor G4 and an Engine Speed Sensor G28 to accomplish this. If either of these sensors go wrong, you will receive codes on the diagnostic scanner which can lead to engine shutdown.
A malfunctioning G28 sensor could cause an inaccurate gearbox speed counter, a gearbox that shifts more quickly than normal, and/or a misfire in the gear. It is possible that the sensor is failing and needs to be replaced if you encounter any of these symptoms. The good news is they are very affordable and readily available, especially if you're looking at an Bosch sensor, which is what we have. You can also choose the GM version of this part is also a good choice.
5. Tachometer
A failing engine sensor could cause a variety of issues within your vehicle. It's an essential component of the transmission in your Audi, as it transmits information to the ECU on how fast or slowly the engine of the car is spinning. If this sensor fails, it could disrupt the performance of the transmission and the other car's components.
The G5 engine sensor is located at the edge of the transmission, over the flywheel ring. It transmits signals via gray wire to ECU pin T55/49. The ECU then uses and processes this signal to control fuel, timig, and boost, and also transmitting it to the G5 tachometer in the instrument cluster. You can test for sensor failure by examining the continuity from the sensor to the tachometer. Additionally, you can verify 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. You should see the resistance to be around 1000 ohms between these points. 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 parts could be found in wrecking yards.