How to Replace an Audi G28 Engine Speed Sensor
In this video Charles the Humble Mechanic shows how to replace the G28 engine speed sensor. The sensor is located near the transmission's edge, above the flywheel gear. It sends a message to the ECU via the grey wire T55/49 and then to the tachometer in the instrument cluster.
1. Engine Speed Sensor
The sensor is located at the edge of the transmission above the flywheel ring gear G28 Engine Speed Sensor sends a signal to ECU pin T55/49 using the grey wire. The ECU utilizes this information to control boost and fuel. It also sends an indicator to the G5 Tachometer within 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 location of the camshaft to trigger the spark and injectors.
If this sensor fails to function, the ECU will display a P00160 error message. This means that the Crank Shaft is out of line with the Intake Camshaft. It could also be a sign of an issue with the chain or a jump in the chain link of the upper chain. The code won't show without the additional information supplied by other sensors (G4 or G40).
Testing can be a bit difficult since there are two connector pins and they perform different functions however the best method of testing it is by measuring resistance between the sensor and the ECU. When the sensor is operational, it should read approximately 1000 ohms. Look for evidence of coolant or oil in the connector bay if there are issues with this component.
2. Injectors
Yesterday, as i was accelerating off the highway paytoll at a high speed, i noticed a huge decrease in power. It was like the engine was running out of gas. Or my injectors were not firing. Today, i pulled out the spark plugs, 3 were soaked with gazoline and the fourth one was dry. I put tissue over each injector hole, and when i turn the engine on without sparks, the ones with gazoline jump right out. The fourth one remains shut. I tested the ground connection of ECU pins 14,30, and 48/55. I got 0ohm. I'm assuming that the issue is somewhere else.
I also tried to reset the 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 still occurs at higher RPM. The coolant sensor (G62) even when it is unplugged, shows an ice temperature of -49c. I also noticed that the oil gauge in the cockpit shows 2 bar while the actual pressure is 0.
I'm not sure what to do. I believe that I've all other possibilities out. But i'm worried that I might have missed something. Let me know If you have any suggestions! TIA!
3. Fuel Pump
The fuel pump of the g28 receives a signal from the RPM sensor. The GM-style transmitter functions here similarly to the G4 sender and works on the 80,100,200, UrS, and RS2 vehicles. You can easily find an extra in a wrecking 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 here bump on the connector's edge facing up). They must be infinite Ohms.
4. ECU
The ECU in our 20vt turbo (3B AAN ABY ADU) engines requires to know both the speed and position of the crankshaft to make decisions regarding timing of the fuel injector, etc. It uses a Crank Position Sensor G4 and an Engine Speed Sensor G28 to achieve this. If either of these go bad you will get check here codes on the diagnostic scanner that could cause engine shut down.
A malfunctioning G28 sensor could click here cause an inaccurate speed counter for the gearbox or a gearbox that shifts faster than normal, and/or a misfire while in gear. It is likely that your sensor is failing and requires to be replaced if you click here encounter any of these signs. The good news is that they are quite affordable and easy to find, especially if you're looking at the Bosch model, which is what we have. If you prefer, GM's version of this part would be a good option.
5. Tachometer
A damaged engine sensor could cause a variety of issues in your vehicle. It's a vital component of your Audi's transmission, since it relays information to the ECU about how fast or slow the vehicle's crankshaft is spinning. If this sensor fails, it will disrupt the performance of the transmission as well as the rest of the car's components.
The G5 engine sensor is located at the edge of the transmission, just above the flywheel ring. It transmits an electrical signal through gray wire to ECU pin T55/49. The ECU uses this signal to regulate the flow of fuel and boost and also timig. It also relays it to the G5 Tachometer located in the instrument cluster. You can check the sensor for failure by checking continuity between it and the tachometer, between the ECU pin T55/49 and the instrument cluster connection on pin T6a/1 (trace [79]) as well as between T6a/1, and the instrument cluster pin T26a/12. You should see the resistance to be around 1000 ohms in these areas. This is a standard part across the Audi 80 100 200, UrS and RS2 range from 1985 MC through the 1997 UrS AAN and 1995 RS2 ADU, so the best ones could be available in wrecking yards.