How to Replace an Audi G28 Engine Speed Sensor
Charles the Humble Technician teaches how to replace the G28 Engine Speed Sensor. The sensor is located at the edge of transmission, above the flywheel gear. It transmits a signal to the ECU via a grey wire T55/49, then to the tachometer in the instrument cluster.
1. Engine Speed Sensor
The grey wire is situated on the edge of transmission, above the flywheel ring. This sensor sends an electrical signal through the grey wire to pin T55/49. The ECU utilizes this information to regulate fuel and boost. It also sends an indication to the G5 tachometer inside the instrument cluster.
The sensor is used to correlate the G40 Camshaft position Sensor. The ecu must know when the crankshaft has reached TDC and also the position of the camshaft, in order to activate the spark and injectors.
If this sensor fails, the ECU will display a P00160 error message. This indicates that the Crank Shaft is not in alignment with the Intake Camshaft. It could also indicate an issue with the chain or a jump in the chain link of the upper timing chain. 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 since there are various pins on the connector, and each one has 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 the sensor is at full operation. Look for signs of coolant, or oil in the connector bay if you are experiencing issues with this part.
2. Injectors
Yesterday accelerating full speed from highway paytoll i had massive power loss as if the engine was running out of gas or injectors aren't firing at all. This morning i pull out the spark plugs, 3 were soaked with gazoline and the fourth one was dry. I placed a tissue over each hole in the injector and when I start the engine with no 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 found zero ohm. I think the issue is elsewhere.
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 problem continues to occur at higher RPM. The coolant sensor (G62) even when it is unplugged, shows an ice temperature of -49c. I also noticed that the gauge for oil pressure in the cockpit is showing 2 audi a3 replacement key bar when the actual pressure is 0.0 when I crank up the engine.
I'm not sure what to do, i believe that i've eliminated everything else. But i'm worried that I may have missed something. If anyone has suggestions, please chime in! TIA!
3. Fuel Pump
The fuel pump in the g28 can be activated by a signal from the RPM sensor. The GM-style transmitter is identical to the G4 sender and both work on the 80,100,200, UrS, and RS2 vehicles. It is easy to find the spare in a salvage shop or parts store. It is easy to test them - just switch your DMM into resistance mode and measure 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 of 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 the fuel injector, etc. It makes use of a Crank Position Sensor G4 and an Engine Speed Sensor G28 to achieve this. If either of these goes wrong, you will receive codes on the diagnostic scanner that can lead to engine shutdown.
The signs of a failed G28 sensor include an inaccurate rev counter for the gearbox, gears shifting quicker than normal and/or misfiring when in gear. It is likely that your sensor is failing and requires to be replaced if you encounter any of these symptoms. They're cheap and easy to find especially if they're a Bosch unit like ours. Alternately, the GM version of this unit is also a good choice.
5. Tachometer
A failing engine speed sensor could be the cause of a slew of issues in your vehicle. It is a crucial part of your Audi's transmission, as it sends information to the ECU about how fast or slow the car's crankshaft is spinning. This sensor can cause the transmission to malfunction and other components in the car to be affected.
The G5 engine sensor is located at the outskirts of transmission, above the more info flywheel ring. It transmits an electrical signal through a gray wire to the ECU pin T55/49. The ECU uses this signal to regulate fuel and boost, and also timig. It also sends it to the G5 Tachometer inside the instrument cluster. You can check for sensor failure by examining the continuity from the sensor to the tachometer. Also, you can check continuity between pin T55/49 of check here the ECU and click here pin T6a/1 of the instrument cluster (trace [79trace [79]) and between pin T6a/1 as well as pin T26a/12. You should observe around 1000 ohms of resistance between these two points. This part is common across the Audi 80-100-200-RS2 range, from the 1985 MC up to the 1997 UrS AN and 1995 audi spare key RS2 DU, so you might find good ones in wrecking yards.