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. This sensor is situated near the transmission's edge just above the flywheel gear. It transmits a signal the ECU via the grey wire (T55/49), then to the tachometer located in the instrument cluster.
1. Engine Speed Sensor
Located on the edge of the transmission just above the flywheel ring gear, the G28 Engine Speed Sensor sends an electrical signal to ECU pin T55/49 using the grey wire. The ECU then uses this information to control the boost, fuel, and timig. It also sends an indication to the G5 Tachometer located in the instrument cluster.
The sensor serves as a reference point to connect with the G40 Camshaft Position Sensor. The ecu has to know when the crankshaft has reached TDC and also the location of the camshaft to trigger the spark and injectors.
If this sensor fails, the ECU will show an error code P00160 which indicates that the Crank Shaft and Intake Camshaft aren't in sync, possibly indicating the chain is stretched or a jump link on the upper chain of timing. However, the error code won't appear on its own without additional information from other sensors (G4 and G40).
Testing is a bit challenging as there are two different connector pins and they perform different functions however the best way to test it is by measuring resistance between the sensor and the ECU. It should read around 1000 ohms when the sensor is at full operation. If you are having problems with this sensor, look for signs of oil or coolant in the connector bay.
2. Injectors
Yesterday, while accelerating at full speed from the highway paytoll, i experienced massive power loss like the engine is running out of gas or the injectors are not firing at all. Today, i pulled out the spark plugs. Three were drenched in gazoline, the fourth one was dry. I put tissue over each hole in the injector and when i start the engine without sparks, the 3 with gazoline jump out. The 4th one remains closed. I inspected the ground connection on ECU pins 14/55,30/55 and 48/55 I get zero Ohm. Therefore, i think the issue is elsewhere.
I also tried to reset PID without success. The car will start when the G28 is unplugged, and it works fine when the G28 connected. However, the intermittent misfire problem continues to occur at higher RPM. The coolant sensor (G62) even when unplugged, still shows an ice temperature of -49c. I also noticed that the gauge for oil pressure in the cockpit is showing 2 bar, whereas the actual pressure is 0.0 when i rev the engine.
audi a4 replacement key www.thekeylab.co.uk 'm not sure what to do, as i feel i have pretty much ruled out everything else. I'm worried that i might have missed something. Let me know should you have any suggestions! TIA!
3. Fuel Pump
The fuel pump of the g28 receives a signal 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 which is why you can easily locate one at a junkyard or from a parts store. It is simple to test them to do - just put your DMM in resistance mode and measure between pins 1 (with the bump on the connector end up) and 2 (2nd from the left on the black connector's end). They should be infinite ohms.
4. ECU
The ECU of our 20vt turbo (3B AAN ABY) engines requires to know the position and speed the crankshaft to determine fuel injector timing, etc. To accomplish this, it makes use of a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If you encounter a problem with either of these sensors, the diagnostic scanner will display the codes that could trigger an engine shutdown.
Some of the symptoms of a malfunctioning G28 sensor include an inaccurate rev counter for the gearbox, gears shifting quicker than normal and/or misfiring 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 cheap and easy to find, especially if you're looking at a Bosch sensor, like ours. You can also choose the GM version of this unit is also a good option.
5. Tachometer
A damaged engine sensor could cause a number of problems in your car. It's an essential component of your Audi's transmission, as it sends information to the ECU about how fast or slow the car's crankshaft is turning. When this sensor fails, it will disrupt the performance of the transmission, as well as the other car's components.
The G5 engine speed sensor is situated on the outside of the transmission above the flywheel ring gear. It sends a signal to the ECU at pin T55/49 through a grey wire. The ECU then uses and processes this signal to regulate the flow of fuel, timig and boost as well as transmitting 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 pin T6a/1 (trace [79trace [79]) and between T6a/1 and the instrument cluster pin T26a/12. You should see around 1000 ohms of resistance between those two pins. This is a standard component across the Audi 80 100 200, UrS and RS2 range from 1985 MC to the 1997 UrS AAN and 1995 RS2 ADU so good ones could be available in wrecking yards.