The 10 Most Worst Audi G28 Mistakes Of All Time Could Have Been Prevented
How to Replace an Audi G28 Engine Speed Sensor
Charles the Humble Technician teaches you how to replace the G28 Engine Speed Sensor. This sensor is located on the edge of the transmission above the flywheel ring gear. It sends a message to the ECU through a grey wire T55/49, then to the tachometer located on the instrument cluster.
1. Engine Speed Sensor
The sensor is located at the edge of the transmission just 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 alert to the G5 Tachometer in instrument cluster.
The sensor is used to link the G40 Camshaft position Sensor. The ecu must know when the crankshaft is TDC and the location of the camshaft so it can activate spark and injectors in the right way.
If this sensor fails the ECU will display the P00160 error, which means the Crank Shaft and Intake Camshaft are out of sync, possibly indicating the chain is stretched or a jump link on the upper chain of timing. The code won't appear without the additional information provided by other sensors (G4 or G40).
It can be a bit difficult to test because there are several pins on the connector and each has its own functions. The best method for doing this is by measuring the resistance between the ECU and the sensor. what is the audi advanced key should read about 1000 ohms when the sensor is operating at its maximum. Look for evidence of coolant or oil in the connector bay if there are issues with this part.
2. Injectors
Yesterday, as i was accelerating off the highway paytoll at a high speed I noticed a massive reduction in power. It was like the engine had run out of gas. Or, my injectors weren't firing. This morning i pull out the spark plugs. Three were soaked with gazoline and the 4th one was dry. I put a piece of tissue over each injector hole and when I start the engine with no sparks, the 3 that have gazoline pop right out. The fourth one remains shut. I checked the ground connection of ECU pins 14,30, and 48/55. I got zero ohm. Therefore, i think the issue is somewhere else.
I also tried to reset the PID with no success. The car is able to start if the G28 is unplugged and it runs perfectly when it is connected but it still is experiencing intermittent misfires at higher RPM. The temperature sensor for the coolant (G62) shows the wrong temperature of that is -49c even after unplugging it. I also noticed that the oil gauge in the cockpit shows 2 bars but the actual pressure is 0.
I'm not sure what to do, as i think i've pretty much completely ruled out all other possibilities. I'm afraid i may have missed something. If anyone has any ideas please share them! TIA!
3. Fuel Pump
The fuel pump of the g28 receives signals from the RPM sensor. The GM-style transmitter is identical to 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 in a local parts store. It is simple to test them by putting your DMM in resistance mode and measure between pins 1 (with the bump on the connector's side up) and 2 (2nd from left on the black connector's end). They must be infinite Ohms.
4. ECU
The ECU of our 20vt turbo (3B AAN ABY ADU) engines requires to know both the speed and position of the crankshaft in order to make a decision about timing of the fuel injector, etc. It utilizes a Crank Position Sensor G4 and an Engine Speed Sensor G28 to accomplish this. If either of these go badly, you will see codes on the diagnostic scanner which could cause engine shut down.
A damaged G28 sensor can cause an inaccurate speed counter for the gearbox, a gearbox that shifts more quickly than normal, or a misfire in gear. It is probable that your sensor is failing and needs to be replaced if you experience any of these symptoms. They're cheap and easy to find, especially when they're a Bosch model like ours. Alternatively, the GM version of this part is also a good option.
5. Tachometer
A damaged engine sensor could cause a variety of issues in your car. It is a crucial part of your Audi's transmission, since it relays information to the ECU about how fast or slow the vehicle's crankshaft is rotating. This sensor can cause the transmission to malfunction 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 transmits a signal to the ECU at pin T55/49 via a grey wire. The ECU then processes the signal to control fuel, timig and boost as well as sends it on 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, between ECU pin T55/49 and the instrument cluster connection on pin T6a/1 (trace [79]) as well as between T6a/1, and the instrument cluster pin T26a/12. There should be a resistance of approximately 1000 ohms in these areas. This part is common across the Audi 80-100-200-RS2 model, ranging from the 1985 MC up to the 1997 UrS AN and 1995 RS2 DU, so you might find them in wrecking yards.