How The 10 Worst Audi G28-Related FAILS Of All Time Could Have Been Prevented
How The 10 Worst Audi G28-Related FAILS Of All Time Could Have Been Prevented
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How to Replace an Audi G28 Engine Speed Sensor
Charles the Humble Technician teaches you how to replace the G28 Engine Speed Sensor. The sensor is located near the edges of the transmission above the flywheel ring gear. It transmits a signal to the ECU via an uncolored wire (T55/49) which is then sent to the tachometer in the instrument cluster.
1. Engine Speed Sensor
Located on the edge of the transmission, above the flywheel ring gear the G28 Engine Speed Sensor sends signals to ECU pin T55/49 using the grey wire. The ECU then utilizes this information to regulate fuel, timig and boost. It also sends an alert to the G5 Tachometer within the instrument cluster.
The sensor serves as a reference to correlate with the G40 Camshaft Position Sensor. The ecu needs to know when the crankshaft has reached TDC, and the location of the camshaft in order to activate the spark and injectors.
If this sensor fails when it fails, the ECU will display a P00160 error code. This indicates that the Crank Shaft is out of alignment with the Intake Camshaft. It could also be a sign of an issue with the chain or a jumpy chain link in the upper timing chain. However, the code won't be displayed on its own without additional information from other sensors (G4 and G40).
Testing can be a bit difficult since there are two pins for the connector and they have different functions however the best method of testing it is by measuring resistance between the sensor and the ECU. It should read approximately 1000 ohms if the sensor is operating at its maximum. Check for signs of coolant or oil in the connector bay if there are problems with this part.
2. Injectors
Yesterday, as i was accelerating off the highway paytoll at a high speed I noticed a massive decrease in power. It was like the engine had run out of gas. Or, my injectors weren't firing. Today, i pulled out the spark plugs. Three were soaked with gazoline and the fourth was dry. When i crank the engine with no sparks, i place a tissue on the top of each hole in the injector, the 3 drenched with gazoline leap out, however the 4th stays closed. I checked the ground connection of ECU pins 14,30 and 48/55. I got 0ohm. I'm assuming the issue is somewhere else.
I also tried to reset the PID with no success. The car will start when the G28 is disconnected and is running fine when it is connected however it is experiencing intermittent misfires at higher RPM. The coolant sensor (G62), even when unplugged, still shows a temperature of -49c. I also noticed that the oil gauge in the cockpit shows 2 bar but the actual pressure is 0.
I'm not sure what to do. I feel like i've pretty much ruled everything else out. But i'm worried that I might have missed something. Please let me know should you have any suggestions! TIA!
3. Fuel Pump
The fuel pump here in the g28 is activated by a signal sent from the RPM sensor. The GM-style transmitter is similar to the G4 sender, and both operate on the 80,100,200, UrS, and RS2 vehicles. It is easy to find the spare in a salvage shop or parts store. It is simple to test them: simply put your DMM into resistance mode and measure the distance between pins 1 and 2 (with the bump at the connector end facing upwards). They should be infinite Ohms.
4. ECU
Our 20vt turbo (3B AAN, check here ABY and ADU) engines are equipped with an ECU that must know the speed and position of the crankshaft in order to make decisions about timing of the fuel injectors, etc. It uses a Crank Position Sensor G4 and an Engine Speed Sensor G28 to achieve this. If either of these goes check here wrong, you will receive codes on the diagnostic scanner that can lead to engine shutdown.
Some of the signs of a malfunctioning G28 sensor include an inaccurate rev counter in the gearbox and gears that shift faster than normal and/or a misfire when you are in gear. It is possible that the sensor is failing and needs to be replaced if you notice any of these signs. They're inexpensive and easy to locate especially if they're a Bosch sensor like ours. Alternatively, GM's version of this component is an excellent choice.
5. Tachometer
A failing engine sensor could cause a number of problems in your car. It's a vital component of your Audi's transmission, as it sends information to the ECU about how fast or slow the car's crankshaft is spinning. When this sensor fails, it could cause problems for the transmission and the other car's components.
The G5 engine sensor is located near the more info edge of transmission, above the flywheel ring. It sends an electrical signal through a gray wire to the ECU pin T55/49. The ECU utilizes this signal to regulate the flow of fuel and boost and also timig. It also sends it to the G5 Tachometer in instrument cluster. You can test the sensor for failure by checking continuity between it and the tachometer, between ECU pin T55/49 and the instrument cluster connection via pin T6a/1 (trace [79]) and between T6a/1 and the instrument cluster pin T26a/12. You should see get more info approximately 1000 ohms resistance between these two points. This is a common 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 might be availble in wrecking yards.