How The 10 Most Disastrous Audi G28 Mistakes Of All Time Could Have Been Avoided
How The 10 Most Disastrous Audi G28 Mistakes Of All Time Could Have Been Avoided
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How to Replace an Audi G28 Engine Speed Sensor
Charles the Humble Technician teaches you how to replace the G28 Engine Speed Sensor. This sensor is located on the outside of the transmission, above the flywheel gear. It transmits a signal to the ECU via an uncolored 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 signals to ECU pin T55/49 through the grey wire. The ECU uses this information to regulate boost and fuel. It also sends an indication to the G5 Tachometer located in the instrument cluster.
The sensor serves as a reference for comparing with the G40 Camshaft Position Sensor. The ecu must know when the crankshaft reached TDC, and the position of the camshaft, in order to activate the spark and injectors.
If this sensor fails, the ECU will display an error code P00160. This means that the Crank Shaft is out of alignment with the Intake Camshaft. It could also be a sign of the possibility of a chain stretch or jump in the chain link of the upper chain of timing. However the code will not appear on its own without additional information from other sensors (G4 and G40).
It can be a bit difficult to test because there are several pins on the connector and they all have different functions. The best way to do it is to measure the resistance between the ECU and the sensor. If the sensor is functional, it should read around 1000 ohms. If you're experiencing issues with this part, check for evidence of coolant or oil in the connector bay.
2. Injectors
Yesterday, while accelerating at full speed from the highway paytoll, I experienced a big cut in power as if the engine was running out of gas or the injectors aren't firing any more. This morning i pull out the spark plugs. Three were drenched in gazoline, the fourth was dry. When I crank the engine without sparks i put tissue on the top of each of the injector holes and the 3 that were drenched in gazoline pop out, but the 4th stay shut. I tried to test the ground connections of ECU pins 14,30, and 48/55. I got 0ohm. So i assume the problem is in another place.
I also tried to reset PID without success. The car will start when the G28 is unplugged, and it works fine when the G28 plugged in. However, the intermittent misfire problem continues to occur at higher RPM. The temperature sensor for the coolant (G62) shows the wrong temp value that is -49c even after unplugging it. I also noticed that the oil gauge in the cockpit shows read more 2 bars but the actual pressure is zero.
I'm not certain what to do, i think i've pretty much eliminated everything else. However, i'm afraid that i might have missed something. Please let me know if you have any ideas! TIA!
3. Fuel Pump
The fuel pump on the g28 is activated by a signal 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 more info vehicles. You can easily locate the spare in a salvage shop or parts store. Test them out to do - just put your DMM in resistance mode and measure between pins 1 (with the bump on the connector's side up) and 2 (2nd from the left on the black connector's side). They should be infinite ohms.
4. ECU
Our 20vt turbo (3B AAN, ABY, and ADU) engines are equipped with an ECU that website needs to be aware of the speed and position of the crankshaft to make a decision about timing of the fuel injectors, etc. To do this, it utilizes a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If either of these goes bad you will get codes on the diagnostic scanner that can lead to engine shutdown.
A damaged G28 sensor can cause an inaccurate speed counter for the gearbox and website a gearbox which shifts faster than normal, and/or a misfire while in the gear. If you experience any of these problems, it is most likely that your sensor is deteriorating and should be replaced. The good news is they are very cheap and easily accessible, especially if you're looking at an Bosch model, which is what ours are. If you prefer, GM's version of this component is a good option.
5. Tachometer
A failing engine sensor could cause a number of problems in your car. It's an essential component of the transmission of your Audi, as it transmits information to the ECU regarding how fast or slowly the engine is spinning. If the sensor fails, it can disrupt the performance of the transmission and the other car's components.
The G5 engine speed sensor is situated on the edge of the transmission above the flywheel ring gear and sends a signal directly to the ECU at pin T55/49 via an uncolored wire. The ECU utilizes this signal to control the flow of fuel and boost and also timig. It also transmits it to the G5 Tachometer inside the instrument cluster. You can test for sensor failure by examining the continuity from the sensor to the tachometer. Also, 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 approximately 1000 ohms of resistance between those two pins. This is a common feature across the Audi 80-100-200-RS2 range, from the 1985 MC up to the 1997 UrS AN and 1995 RS2 audi keys replacement DU So, you may find good ones in wrecking yards.