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. This sensor is situated on the outside of the transmission over the flywheel gear. It sends a signal to the ECU via the grey wire (T55/49) which is then sent to the tachometer located in the instrument cluster.
1. Engine Speed Sensor
The sensor is located at the edge of the transmission just above the flywheel ring gear the G28 Engine Speed Sensor sends signals to ECU pin T55/49 via the grey wire. The ECU then uses this information to control fuel, timig and boost. It also sends an alert to the G5 Tachometer in instrument cluster.
The sensor is used as a reference for comparing with the G40 Camshaft Position Sensor. The ecu must know when the crankshaft reached TDC and also the location of the camshaft in order to activate the spark and injectors.
If this sensor fails, the ECU will display a P00160 error code. This means that the Crank Shaft is not in line with the Intake Camshaft. It could also be a sign of an issue with the chain or a jumped chain link in the upper timing chain. The code will not appear without the additional information provided by other sensors (G4 or G40).
Testing is a bit tricky as there are two different connector pins, and they serve different purposes however the best way to test it is to measure resistance between the sensor and the ECU. It should read approximately 1000 ohms when the sensor is operating at its maximum. If you're experiencing issues with this sensor, look for signs of coolant or oil in the connector bay.
2. Injectors
Yesterday, when accelerating from highway paytoll at a high speed, i noticed a huge decrease in power. It was as if the engine had run out of gas. Or, my injectors weren't firing. I took out the spark plugs this morning, three were soaked in gasoline, and the 4th was dry. I placed a tissue over each injector hole, and when i start the engine with no sparks, the 3 with gazoline jump right out. The 4th one stays closed. I checked the ground connection on ECU pins 14/55/30/55/48/55/14/55/48/ I get 0ohm. I think the issue is somewhere else.
I also tried to reset the PID with no success. The car will start when the G28 is unplugged, and it runs fine with the G28 connected. However the intermittent misfire issue continues to occur at higher RPM. The coolant sensor (G62), even when unplugged, still shows a temperature of -49c. I also noticed that the oil gauge in the cockpit shows 2 bar when the actual pressure is zero.
I don't know what to do. I believe that I've all other possibilities out. But i'm worried that I might have missed check here something. Please let me know if you have any ideas! TIA!
3. Fuel Pump
The fuel pump of the g28 receives a signal from the RPM sensor. The GM-style transmitter is similar 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 a parts store. It is simple to test them to do - just put your DMM in resistance mode and measure the resistance between pins 1 (with the bump on the connector's end up) and 2 (2nd from left on the black end of the connector). They must be more info infinite Ohms.
4. ECU
The ECU in our 20vt turbo (3B AAN ABY) engines requires to know the position and speed of the crankshaft to determine timing of fuel injectors, etc. To accomplish this, read more it utilizes a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If either of these go bad you will get codes on the diagnostic scanner which could cause engine shut down.
The signs of a failed click here G28 sensor are an inaccurate rev counter in the gearbox and gears that shift faster than normal, and/or a misfire when you're in gear. If you have any of these problems, it is likely your sensor is failing and needs replacing. They're cheap and easy to find particularly in the case of an Bosch model like ours. Alternately, GM's version this part would be an option.
5. Tachometer
A failing engine here sensor could cause a number of problems in your car. It's an essential component of your Audi's transmission, since it relays information to the ECU about how fast or slow the vehicle's crankshaft is rotating. When this sensor fails, it can cause problems for the transmission and the other car's components.
The G5 engine speed sensor is situated on the outside of the transmission above the flywheel ring gear. It transmits a signal to the ECU at pin T55/49 through a grey wire. The ECU is then able to process this signal to control fuel, timig and boost, and also sends it on to the G5 tachometer in the instrument cluster. You can test the sensor for failure by examining the continuity between it and the tachometer, between the ECU pin T55/49 and the instrument cluster connection to pin T6a/1 (trace [79trace [79]) as well as between T6a/1, and the instrument cluster pin T26a/12. You should see a resistance of approximately 1000 ohms in these areas. This is a common feature across the Audi 80-100-200-RS2 range, beginning with the 1985 MC and up to the 1997 UrS An and 1995 RS2 Du, so you might find good ones in wrecking yards.