10 Reasons You'll Need To Be Aware Of Audi G28
10 Reasons You'll Need To Be Aware Of Audi G28
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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 located at the edge of transmission over the flywheel gear. It sends a message to the ECU through an uncolored 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 signals to ECU pin T55/49 through a grey wire. The ECU uses this information to regulate fuel and boost. It also sends an indication 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 be aware of when the crankshaft has reached TDC, and the location of the camshaft to trigger the spark and injectors.
If this sensor fails the ECU will display an error code P00160 which indicates that the Crank Shaft and Intake Camshaft aren't in sync and possibly indicating the chain is stretched or a jump link on the upper timing chain. However, the error code won't appear on its own, without additional information from other sensors (G4 and G40).
Testing is a bit tricky as there are two different connector pins, and they serve different purposes but the best method to test it is to measure the resistance between the sensor and the ECU. It should read approximately 1000 ohms when the sensor is at full operation. If you're experiencing issues 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 a big cut in power like the engine is running out of gas or the injectors are not firing anymore. This morning i pull out the spark plugs. Three were drenched with gazoline the 4th one was dry. When i crank the engine without sparks, i place a tissue on the top of each of the injector holes and the 3 drenched with gazoline leap out, however the 4th stay shut. I inspected the ground connection on ECU pins 14/55, 30/55 and 48/55. I get zero ohm. I'm assuming the issue is somewhere else.
I also tried to reset the PID but without success. The car will start when the G28 is unplugged, and it runs fine with the here G28 plugged read more in. However the intermittent misfire issue still occurs at higher RPM. The temperature sensor for the coolant (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'm not sure what to do, as i believe that i've eliminated everything else. But i am afraid i might have missed something. Please let me know if you have any ideas! 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 read more both are used in the 80 100, 200, UrS and RS2 cars which is why you can easily locate one at a wrecking yard or in a local parts store. Testing them is easy - put your DMM in resistance mode and measure the resistance between pins 1 (with the bump on the connector's side up) and 2 (2nd from left on the black connector's end). They should be infinite here ohms.
4. ECU
The ECU in our 20vt turbo (3B AAN ABY ADU) engines requires to be aware of the position and speed of the crankshaft in order to make a decision about timing of fuel injectors, etc. It uses a Crank Position Sensor G4 and an Engine Speed Sensor G28 to achieve this. If either of these goes bad you will get codes on the diagnostic scanner that could cause engine 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're in gear. If you are experiencing any of these issues it is most likely that your sensor is deteriorating and needs replacing. They're cheap and easy to find particularly when they're a Bosch unit like ours. If you prefer, GM's version of this part would be a good option.
5. Tachometer
A failing engine sensor could cause a myriad of issues in your car. It is a crucial part of the Audi's transmission as it sends information to the ECU about how fast or slow the vehicle's crankshaft is turning. This sensor could cause the transmission to fail and other car components 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 a grey wire. The ECU is then able to process this signal to control fuel, timig, and boost website and then sends it on to the G5 tachometer inside the instrument cluster. You can test for sensor failure by examining the continuity of the sensor to the tachometer. Also, you can verify continuity between pin T55/49 of the ECU and pin T6a/1 of the instrument cluster (trace [79]) and between pin T6a/1 and pin T26a/12. There should be an average resistance of 1000 ohms between these two points. This is a typical part that is found across the Audi 80 100 200, UrS and RS2 range from 1985 MC until the 1997 UrS AAN and 1995 RS2 ADU so good ones could be available in wrecking yards.