Your Worst Nightmare Concerning Audi G28 It's Coming To Life
How to Replace an Audi G28 Engine Speed Sensor
In this video Charles the humble mechanic demonstrates how to replace the G28 engine speed sensor. The sensor is located at the top of the transmission just above the flywheel ring gear. It transmits a signal the ECU via the grey wire (T55/49), 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, the G28 Engine Speed Sensor sends an electrical signal to ECU pin T55/49 via an uncolored 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 inside the instrument cluster.
The sensor is used to connect the G40 Camshaft position Sensor. The ecu needs to know when the crankshaft is TDC and where the camshaft is located so that it can trigger spark and injectors according to the situation.
If this sensor fails when it fails, the ECU will display a P00160 error code. This indicates that the Crank Shaft is out of line with the Intake Camshaft. It could also indicate an issue with the chain or a jump in the chain link of the upper timing chain. However, the error code won't appear on its own without additional information from other sensors (G4 and G40).
Testing can be a bit difficult since there are two connector pins and they have different functions however the best method to test it is by measuring resistance between the sensor and the ECU. It should read approximately 1000 ohms when the sensor is in full operation. Check for spare audi key cost of coolant, or oil in the connector bay if you are experiencing issues with this part.
2. Injectors
Yesterday, when i was accelerating to the fullest speed from highway paytoll, I experienced a big cut in power like the engine is out of gas or the injectors are not firing anymore. In the morning, i removed the spark plugs. Three were drenched in gazoline, the 4th one was dry. When I start the engine without sparks, I put a piece of tissue on the top of each hole in the injector, the 3 drenched with gazoline leap out, however the 4th one stays closed. I checked the ground connection on ECU pins 14/55, 30/55 and 48/55. I get zero ohm. I assume that the problem is somewhere else.
I also tried to reset the PID with no success. The car can start if the G28 is disconnected and runs fine when it is connected however it has the intermittent misfire issue at higher RPM. The temperature sensor for coolant (G62) shows the wrong temperature of -49c even when i unplug it. I also noticed that the oil gauge in the cockpit shows 2 bar when the actual pressure is zero.
I'm not sure what to do. I believe that I've all other possibilities out. I'm worried that i might have missed something. Let me know should you have any suggestions! TIA!
3. Fuel Pump
The fuel pump in the g28 receives signals from the RPM sensor. The GM-style transmitter is the same as the G4 and both are used 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. Test them out to do - just put your DMM in resistance mode and take measurements between pins 1 (with the bump on the connector end up) and 2 (2nd from the left on the black connector's end). They must be infinite Ohms.
4. ECU
The ECU in our 20vt turbo (3B AAN ABY) engines must know both the speed and position of the crankshaft to make decisions regarding fuel injector timing, etc. It uses a Crank Position Sensor G4 and an Engine Speed Sensor G28 to accomplish this. If either of these sensors go wrong, you will receive codes on the diagnostic scanner that can lead to engine shutdown.
A malfunctioning G28 sensor could cause an inaccurate gearbox speed counter and a gearbox which shifts faster than normal, or a misfire in gear. It is likely that the sensor is failing and needs to be replaced if you encounter any of these symptoms. The good news is they are very cheap and readily available particularly if you're looking at an Bosch sensor, like ours. You can also choose the GM version of this component is also a good option.
5. Tachometer
A malfunctioning engine speed sensor could be a cause for a slew of issues in your vehicle. It's an essential component of your Audi's transmission, because it communicates to the ECU about how the car's crankshaft is rotating. If the sensor fails, it can disrupt the performance of the transmission and the rest of the car's components.
The G5 engine speed sensor is situated on the edge of the transmission just above the flywheel ring gear and transmits a signal to the ECU at pin T55/49 through a grey wire. The ECU utilizes this signal to regulate the amount of fuel and boost, and also timig. It also transmits it to the G5 Tachometer inside the instrument cluster. You can check the sensor for any failure by checking the continuity between it and the tachometer. You can also check continuity between ECU pin T55/49 and the instrument cluster connection via pin T6a/1 (trace [79]) and between pin T6a/1 and the instrument cluster pin T26a/12. You should see an average resistance of 1000 ohms between these points. This is a typical part across the Audi 80, 100 200, UrS and RS2 range from 1985 MC to the 1997 UrS AAN and 1995 RS2 ADU. Good ones could be available in wrecking yards.