Audi G28: The Good, The Bad, And The Ugly
Audi G28: The Good, The Bad, And The Ugly
Blog Article
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. The sensor is situated at the top of the transmission just above the flywheel ring gear. It transmits a signal the ECU via a grey wire (T55/49) and then to the tachometer within the instrument cluster.
1. Engine Speed Sensor
It is located on the outside of the transmission just above the flywheel ring gear G28 Engine Speed Sensor sends an electrical signal to ECU pin T55/49 using a grey wire. The ECU uses this information to control boost and fuel. It also sends an indicator to the G5 Tachometer within the instrument cluster.
The sensor is used as a reference for comparing with the G40 Camshaft Position Sensor. The ecu must know when the crankshaft is TDC and where the camshaft is so it can start spark and injectors accordingly.
If this sensor fails when it fails, the ECU will display an error code P00160. This indicates that the Crank Shaft is not in alignment with the Intake Camshaft. It could also be a sign of the possibility of a chain stretch or jumpy chain link in the upper timing chain. However, the error code won't be displayed on its own without additional information from other sensors (G4 and G40).
Testing is a bit tricky as there are two different pins for the connector and they serve different purposes but the most effective way to test it is to measure the resistance between the sensor and the ECU. When the sensor is fully operational, it should read around 1000 ohms. Examine for evidence of coolant or oil in the connector bay if you are experiencing issues with this component.
2. Injectors
Yesterday, while accelerating at full speed from the highway paytoll, i experienced massive power loss as if the engine was running out of gas or the injectors aren't firing any more. In the morning, i removed the spark plugs. Three were drenched with gazoline the fourth was dry. When I crank the engine with no sparks, i place a tissue on top of each injector hole and the 3 that were drenched in gazoline leap out, however the 4th one stays closed. I inspected the ground connection on ECU pins 14/55, 30/55 and 48/55. audi replacement keys I get zero Ohm. I'm assuming the issue is in another place.
I also tried to reset the PID without success. The car will start if the G28 is not plugged in and it runs perfectly when it is plugged in but it still has the intermittent misfire issue at higher RPM. The coolant sensor (G62) even if it is not plugged in, shows temperatures of -49c. I also noticed that the gauge here for oil pressure in the cockpit shows 2 bar, whereas the actual pressure is 0.0 when i rev the engine.
I don't know what to do. I think I've ruled everything else out. I'm afraid i may have missed something. Let me know if you have any ideas! TIA!
3. Fuel Pump
The fuel pump of the g28 receives signals from the RPM sensor. The GM-style sender is the same as the G4 and they both work in the 80, 100 200, UrS and RS2 cars so you can easily find one at a salvage yard or at a parts store. Test them out by putting your DMM in resistance mode and measure between pins 1 (with the bump on the connector end up) and 2 (2nd from left on the black connector's side). They should be infinite Ohms.
4. ECU
The ECU in our 20vt turbo (3B AAN ABY ADU) engines requires to know both the position and speed the crankshaft to make decisions regarding timing of the fuel injector, etc. In order to do this it uses a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If either of these go badly, you will see codes on the diagnostic scanner that can cause the engine to shut down.
The signs of a malfunctioning G28 sensor are an inaccurate rev counter in the gearbox, gears shifting quicker than normal and/or misfiring when you are in gear. It is possible that your sensor is failing and requires to be replaced if you experience any of these signs. They're inexpensive and easy to locate particularly in the case of an Bosch model like ours. Alternately, GM's version this component is an excellent choice.
5. Tachometer
A failing engine speed sensor could be the reason behind a slew of issues with your car. It's an essential component of the Audi's transmission as it sends information to the ECU about how fast or slow the vehicle's crankshaft is spinning. This sensor could cause the transmission to malfunction and other components in the car to be affected.
The G5 engine speed sensor is situated on the edge of the transmission, above the flywheel ring gear and audi spare keys transmits a signal to the ECU at pin T55/49 through a grey wire. The ECU uses this signal to control 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 failure by examining the continuity between it and the tachometer. You can also check continuity between ECU pin T55/49 and the instrument read more cluster connection to pin T6a/1 (trace [79trace [79]) and between pin T6a/1 and the instrument cluster pin T26a/12. You should detect an average resistance of 1000 ohms between these two points. This is a typical part that is audi a4 spare key found across the Audi 80, 100 200, UrS and RS2 range from 1985 MC through the 1997 UrS AAN and 1995 RS2 ADU, so the best parts could be found in wrecking yards.