In this video Charles the humble mechanic demonstrates how to replace the G28 engine speed sensor. The sensor is located on the outside of the transmission, above 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 SensorIt is located on the outside of the transmission above the flywheel ring gear, the G28 Engine Speed Sensor sends a signal to ECU pin T55/49 through a grey wire. The ECU then utilizes this information to regulate the flow of fuel, timig and boost. It also sends an indication to the G5 tachometer in the instrument cluster.
The sensor is used as a reference for comparing with the G40 Camshaft Position Sensor. The ecu needs to know when the crankshaft is TDC and the location of the camshaft so it can start spark and injectors according to the situation.
If this sensor fails the ECU will display an error code P00160 which indicates that the Crank Shaft and Intake Camshaft are out of sync and possibly indicating the chain is stretched or a jump link on the upper chain of timing. 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 pins for the connector and they serve different purposes but the most effective method to test it is to measure resistance between the sensor and the ECU. It should read approximately 1000 ohms when the sensor is in full operation. Examine for signs of coolant, or oil in the connector bay if you are experiencing issues with this part.
2. Injectors
Yesterday, while accelerating from the highway paytoll at maximum speed I noticed a massive drop in power. It was like the engine had run out of gas. Or my injectors were not firing. In the morning, i removed the spark plugs, 3 were drenched with gazoline the fourth was dry. I placed a tissue over each injector hole, and when I start the engine without sparks, the ones with gazoline jump right out. The fourth one remains shut. I tested the ground connection on ECU pins 14/55/30/55/48/55/14/55/48/ I got 0ohm. I think the issue is somewhere else.
I also tried to reset the PID but with no luck. The car will start when the G28 is unplugged, and it is running fine with the G28 plugged in. However the intermittent misfire issue continues to occur at higher RPM. The coolant temperature sensor (G62) shows the wrong temperature value of -49c, even if I unplug it. I also noticed that the oil gauge in the cockpit shows 2 bar while the actual pressure is zero.
I don't know what to do. I believe that I've all other possibilities out. However, i'm afraid that i might have missed something. If anyone has suggestions, please chime in! TIA!
3. Fuel Pump
The fuel pump in the g28 is activated by a signal by the RPM sensor. The GM-style sender is the same as the G4 and they both work in the 80, 100 200, UrS and audi advanced key A1 key (padilla-gonzalez.Hubstack.net) RS2 cars so you can easily find one at a wrecking yard or from a parts store. It is simple to test them by putting your DMM in resistance mode and take measurements between pins 1 (with the bump on the connector's end up) and 2 (2nd from the left on the black end of the connector). They must be infinite Ohms.
4. ECU
The ECU in our 20vt turbo (3B AAN ABY ADU) engines needs to 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 achieve this. If either of these sensors go bad you will get codes on the diagnostic scanner which can lead to engine shutdown.
The signs of a failing G28 sensor include an inaccurate rev counter in the gearbox the gears are shifting faster than normal, and/or a misfire when you are in gear. If you experience any of these issues it is likely your sensor is deteriorating and should be replaced. The good thing is that they are quite affordable and easily accessible particularly if you're looking at a Bosch unit like ours. You can also choose the GM version of this unit is also a good choice.
5. Tachometer
A failing engine speed sensor could be a cause for numerous issues with your car. It's a vital component of the audi replacement key fob's transmission because it communicates to the ECU about how fast or slow the car's crankshaft is rotating. This sensor could cause the transmission to fail and other components of the car to be affected.
The G5 engine speed sensor is located at the edge of the transmission, above the flywheel ring gear and sends a signal to the ECU at pin T55/49 through an uncolored wire. The ECU uses this signal to regulate the amount of fuel and boost, as well as timig. It also sends it to the G5 Tachometer inside the instrument cluster. You can test for sensor failure by examining the continuity from the sensor to the tachometer. You can also verify continuity between pin T55/49 of the ECU and pin T6a/1 of the instrument cluster (trace [79trace [79]), and between pin T6a/1 and pin T26a/12. You should see around 1000 ohms of resistance between those points. This is a common feature across the audi key programmer 80-100-200-RS2 series, starting from the 1985 MC up to the 1997 UrS AN and 1995 RS2 Du So, you may find some good ones in wrecking yards.
