How to Replace an Audi G28 Engine Speed Sensor
Charles the Humble Technician shows how to replace the G28 Engine Speed Sensor. The sensor is located on the outside of the transmission over the flywheel gear. It sends a message to the ECU through the grey wire T55/49 and then to the tachometer located 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 using the grey wire. The ECU uses this information to control boost and fuel. It also sends an indicator to the G5 Tachometer located in the instrument cluster.
The sensor is used as a reference to correlate with the G40 Camshaft Position Sensor. The ecu must know when the crankshaft has reached TDC, and the position of the camshaft, in order to activate the spark and injectors.
If this sensor fails the ECU will throw the P00160 error, which means the Crank Shaft and Intake Camshaft are not in sync and possibly indicating chain stretch or a jumped link on the upper chain of timing. The code won't appear without the additional information provided by other sensors (G4 or G40).
It's a bit tricky to test as there are several 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. When the sensor is operational, it should read approximately 1000 ohms. If you're experiencing issues with this part, check for signs of coolant or oil in the connector bay.
2. Injectors
Yesterday, while accelerating from the highway paytoll at full speed I noticed a massive reduction in power. It was as if the engine had run out of gas. Or my injectors were not firing. I pulled out the spark plugs this morning, three were soaked with gasoline and the fourth was unclean. I put tissue over each hole in the injector and when i start the engine without sparks, the three with gazoline jump out. The fourth one remains shut. I tried to test the ground connections of ECU pins 14,30 and 48/55. I got 0ohm. I assume that the problem is somewhere else.
I also tried to reset PID without success. The car will start when the G28 is disconnected, but it works fine when the G28 plugged in. However, the intermittent misfire problem audi spare key replacement still occurs at higher RPM. The coolant sensor (G62) even when it is unplugged, shows temperatures of -49c. 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, as i believe that i've eliminated everything else. But i am afraid I may have missed something. Let me know if you have any ideas! TIA!
3. Fuel Pump
The fuel pump in the g28 can be activated by a signal sent by the RPM sensor. The GM-style transmitter is similar to the G4 sender, and both operate on the 80,100,200, UrS, and RS2 vehicles. It is easy to find a spare in a wrecking shop or parts store. Testing them is easy to do - just put your DMM in resistance mode and measure between pins 1 (with the bump on the connector's end up) and 2 (2nd from left on the black connector's side). They should be infinite ohms.
4. ECU
The ECU in our 20vt turbo (3B AAN lost audi keys ABY) engines must know the speed and position of the crankshaft in order to make a decision about timing of the fuel injector, etc. It uses a Crank Position Sensor G4 and an Engine Speed Sensor G28 to accomplish this. If either of these goes bad you will get codes on the diagnostic scanner that could cause engine shut down.
The signs of a failing G28 sensor are an inaccurate gearbox rev counter the gears are shifting faster than normal and/or a misfire when you are in gear. If you have any of these issues it is likely that your sensor is failing and needs replacing. They're cheap and easy to find especially when they're a Bosch sensor like ours. Alternately, the GM version of this part is also a good choice.
5. Tachometer
A malfunctioning engine speed sensor could be the reason behind a slew of issues in your car. It's an essential component of the transmission in your Audi because it relays information to the ECU regarding how fast or slow the engine of the car is turning. This sensor could cause the transmission to fail and other car components to be affected.
The G5 engine sensor is located at the edge of transmission, above the flywheel ring. It sends an electrical signal through a gray wire to the ECU pin T55/49. The ECU utilizes this signal to control the amount of fuel and boost, and also timig. It also sends it click here to the G5 Tachometer located in the instrument cluster. You can determine if the sensor is in failure by examining the continuity from the sensor to the tachometer. You can also examine the continuity between audi a1 keys pins T55/49 of the ECU and pin T6a/1 of the instrument cluster (trace [79]), and between pin T6a/1 and pin T26a/12. You should see an average resistance of 1000 ohms between these two points. This part is common across the Audi 80-100-200-RS2 series, starting beginning with the 1985 MC and up replacement audi key to the 1997 UrS An and 1995 RS2 Du So, you may find them in wrecking yards.