How to Replace an Audi G28 Engine Speed Sensor
Charles the Humble Technician teaches how to replace the G28 Engine Speed Sensor. This sensor is situated near the transmission's edge over the flywheel gear. It sends a signal to the ECU via an uncolored wire (T55/49) which is then sent to the tachometer within the instrument cluster.
1. Engine Speed Sensor
The grey wire is located at the edges of the transmission, directly above the flywheel ring. The sensor transmits a signal via the grey wire to pin T55/49. The ECU then uses this information to control the boost, fuel, and timig. It also sends an indicator to the G5 Tachometer in instrument cluster.
The sensor is used to link the G40 Camshaft position Sensor. The ecu needs to know when the crankshaft is TDC and where the camshaft is so it can start spark and injectors in the right way.
If this sensor fails, the ECU will display a P00160 error message. This indicates that the Crank Shaft is out of sync with the Intake Camshaft. It could also indicate the possibility of a chain stretch or jump in the chain link of the upper timing chain. The code will not appear without the additional information supplied by other sensors (G4 or G40).
Testing is a bit tricky as there are two different connector pins, and they perform different functions however the best method of testing it is to measure the resistance between the sensor and the ECU. It should read around 1000 ohms if the sensor is at full operation. Examine for signs of coolant or oil in the connector bay if you are experiencing issues with this component.
2. Injectors
Yesterday, as i was accelerating off the highway paytoll at maximum speed I noticed a significant reduction in power. It was as if the engine was running out of gas. Or, my injectors weren't firing. I took out the spark plugs this morning, 3 were soaked with gasoline and the fourth was unclean. I put a piece of tissue over each injector hole, and when I start the engine without sparks, the ones with gazoline jump right out. The 4th one stays closed. I tested the ground connection on ECU pins 14/55/30/55/48/55/14/55/48/ I get 0ohm. I'm assuming the issue is somewhere else.
I also tried to reset PID without success. The car is able to start when the G28 is disconnected and is running fine when it is plugged check here in, but still has intermittent misfire issues at higher RPM. The coolant sensor (G62), even if it is not plugged in, shows temperatures of -49c. I also noticed that the oil pressure gauge in the cockpit is showing 2 bar while the actual pressure is 0.0 if i crank up the engine.
I'm not sure what to do, but i think i've pretty much completely ruled out all other possibilities. I'm worried that i might have missed something. Please let me know if you have any ideas! TIA!
3. Fuel Pump
The fuel pump in the g28 receives signals from the RPM sensor. The GM-style transmitter is identical to the G4 and they both work in the 80 100, 200, UrS and RS2 cars so you can easily find one at a wrecking yard or in a local parts store. It is simple to test them - just switch your DMM into resistance mode and determine the distance between pins 1 and 2 (with the bump on the connector's edge facing upwards). They should be infinite ohms.
4. ECU
The ECU of our 20vt turbo (3B AAN ABY ADU) engines must know the position and speed the crankshaft in order to make a decision about timing of fuel injectors, etc. It utilizes a Crank Position Sensor G4 and an Engine Speed Sensor G28 to accomplish this. If you encounter a problem with either one of these, the diagnostic scanner will show the codes that could trigger an engine shut down.
A malfunctioning click here G28 sensor could result in an inaccurate speed counter for your gearbox, a gearbox that shifts faster than normal, or an unfire when in gear. If you experience any of these issues it is most likely that your sensor is going bad and requires replacement. The good thing is that they are very cheap and readily available, especially if you're looking at the Bosch model, like ours. If you prefer, GM's version of this component is a good option.
5. Tachometer
A faulty engine speed sensor could be the reason behind a slew of issues with your car. It is an important part of the transmission in your Audi, as it transmits information to the ECU about how fast or slowly the car's get more info engine is turning. If this sensor fails, it can cause problems for the transmission as well as the rest of the car's components.
The G5 engine sensor is located near the edge of transmission, above the flywheel ring. It get more info sends signals via a gray wire to the ECU pin T55/49. The ECU utilizes this signal to regulate the amount of fuel and boost, as well as timig. It also relays it to the G5 Tachometer located in the instrument cluster. You can test the sensor for failure by checking continuity between it and the tachometer. You can also check continuity between ECU pin T55/49 and the instrument cluster connection to more info pin T6a/1 (trace [79]) as well as between T6a/1, and the instrument cluster pin T26a/12. There should be an average resistance of 1000 ohms in these areas. This is a common part across the Audi 80, 100, 200, UrS and RS2 range from 1985 MC through the 1997 UrS AAN and 1995 RS2 ADU so good ones might be availble in wrecking yards.