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 on the edge of the transmission, above the flywheel ring gear. It transmits a signal to the ECU through a grey wire T55/49, then to the tachometer on the instrument cluster.
1. Engine Speed Sensor
The grey wire is located on the outside of the transmission, directly above the flywheel ring. The sensor transmits an electrical signal through the grey wire to pin T55/49. The ECU uses this information to regulate boost and fuel. It also sends an alert to the G5 Tachometer in instrument cluster.
The sensor is used to correlate with the G40 Camshaft position Sensor. The ecu must know when the crankshaft reached TDC and also the position of the camshaft, so that it can activate the spark and injectors.
If this sensor fails to function, the ECU will display a P00160 error code. This means that the Crank Shaft is not in sync with the Intake Camshaft. It could also be a sign of an issue with the chain or a jumpy chain link in the upper chain of timing. The code won't appear without the additional information supplied by other sensors (G4 or G40).
It can be a bit difficult to test since there are several connector pins, 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 around 1000 ohms when the sensor is at full operation. If you're having issues with this component, look for evidence of coolant or oil in the connector bay.
2. Injectors
Yesterday accelerating full speed from highway paytoll, I experienced a big cut in power as if the engine was running out of gas or injectors are not firing at all. I pulled out the spark plugs this morning, three were soaked with gasoline and the 4th was dry. When I start the engine, there are no sparks, i place a tissue on the top of each hole in the injector and the 3 that were drenched in gazoline pop out, but the 4th one stays shut. I checked the ground connection of ECU pins 14,30, and 48/55. I found 0ohm. I think the issue is elsewhere.
I also tried to reset the PID but without success. The car will start when the G28 is unplugged, and it works fine when the G28 connected. However, the intermittent misfire problem still occurs at higher RPM. The temperature sensor for the coolant (G62) shows the wrong temp value that is -49c even after unplugging it. Also, i noticed that the oil pressure gauge in the cockpit shows 2 bar when the actual pressure is 0.0 if i crank audi key replacement up the engine.
I'm not sure what to do. I believe that I've ruled everything else out. I'm concerned that i may have missed something. Please let me know If you have any suggestions! TIA!
3. Fuel Pump
The fuel pump on the g28 is activated by a signal sent by the RPM sensor. The GM-style sensor is identical to the G4 and they both work in the 80 100, 200, UrS and RS2 cars which is why you can easily locate one at a salvage yard or from a parts store. It is easy to test them: simply switch your DMM into resistance mode and measure the distance between pins 1 and 2 (with the bump on the connector's edge facing upwards). They must be infinite ohms.
4. ECU
Our 20vt turbo (3B AAN, ABY, and ADU) engines are equipped with an ECU that needs to know website the speed and position of the crankshaft in order to make decisions about fuel injector lost audi keys timing etc. It utilizes 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.
Some of the symptoms of a failing G28 sensor include an inaccurate rev counter in the gearbox, gears shifting audi lost key replacement quicker than normal and/or a misfire when in gear. It is possible that your sensor is failing and needs to be replaced if you experience any of these symptoms. The good thing is that they are very affordable and easily accessible, especially if you're looking at an Bosch sensor, which is what we have. Alternatively, the GM version of this component is also a good choice.
5. Tachometer
A malfunctioning engine speed sensor could be a cause for a slew of problems in your vehicle. It is an important part of here the transmission in your Audi because it relays information to the ECU regarding how fast or slowly the car's engine is spinning. This sensor could cause the transmission to malfunction and other car components to be affected.
The G5 engine speed sensor is located on the outside of the transmission above the flywheel ring gear. It sends a signal directly to the ECU at pin T55/49, via an uncolored wire. The ECU uses this signal to control fuel and boost, and also timig. It also transmits it to the G5 Tachometer in instrument cluster. You can test the sensor for any failure by checking the continuity between it and the tachometer, between ECU pin T55/49 and the instrument cluster connection on pin T6a/1 (trace [79trace [79]) as well as between T6a/1, and the instrument cluster pin T26a/12. It should show around 1000 ohms of resistance between those points. This is a common component across the Audi 80, 100, 200, UrS and RS2 range from 1985 MC through the 1997 UrS AAN and 1995 RS2 ADU so good parts could be found in wrecking yards.