20 Myths About Audi G28: Busted
20 Myths About Audi G28: Busted
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How to Replace an Audi G28 Engine Speed Sensor
Charles the Humble Technician teaches how to replace the G28 Engine Speed Sensor. This sensor is located at the top of the transmission just above the flywheel ring gear. It transmits a signal the ECU via a grey wire (T55/49), then to the tachometer located 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 via a grey wire. The ECU then utilizes this information to regulate fuel, timig and boost. It also sends an indication to the G5 Tachometer in instrument cluster.
The sensor is used as a reference point to connect with the G40 Camshaft Position Sensor. The ecu must know when the crankshaft is TDC and the location of the camshaft so it can trigger spark and injectors accordingly.
If this sensor fails, the ECU will throw a P00160 code which means the Crank Shaft and Intake Camshaft aren't in sync and could indicate the chain is stretched or a jump link on the upper timing chain. The code will not appear without the additional information supplied by other sensors (G4 or G40).
It's a bit tricky to test since there are various connector pins, and each one has different functions. The most effective method to test it is to measure the resistance between the ECU and the sensor. It should read around 1000 ohms if the sensor is operating at its maximum. Look for signs of coolant or oil in the connector bay if you are experiencing problems with this part.
2. Injectors
Yesterday accelerating full speed from highway paytoll, i experienced massive power loss like the engine is running out of gas or injectors aren't firing anymore. This morning i pull out the spark plugs, 3 were drenched in gazoline, the fourth was dry. I put a piece of tissue over each hole in the injector and when I start the engine without sparks, the three with gazoline jump right out. The 4th one stays closed. I tested the ground connection of ECU pins 14,30 and 48/55. I got 0ohm. I'm assuming that the issue is in another location.
I also tried to reset the PID without success. The car will start when the G28 is unplugged, and it runs fine with the G28 connected. However, the intermittent misfire problem continues to occur at higher RPM. The coolant sensor (G62), even when it is unplugged, shows a temperature of -49c. I also noticed that the oil gauge in the cockpit shows 2 bar but the actual pressure is zero.
I'm not sure what to do. I think I've eliminated everything else. But i'm worried that I might have missed something. Let me know should you have any suggestions! TIA!
3. Fuel Pump
The fuel pump in the g28 can be activated by a signal from the RPM sensor. The GM-style sensor genuine audi key replacement is identical to the G4 and they both work in the 80, 100 200, UrS and RS2 cars so you can easily find one at a junkyard or from a 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 end up) and 2 (2nd from the left on the black end of the connector). They must be infinite Ohms.
4. ECU
The ECU in our 20vt turbo (3B AAN ABY ADU) engines needs to know the position and speed the crankshaft to determine fuel injector timing, etc. In order to do this it utilizes a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If you encounter a problem with either of these, the diagnostic scanner will display codes that could lead to an engine shut down.
Some of the symptoms of a malfunctioning G28 sensor include an audi advanced key inaccurate rev counter for the gearbox and gears that shift faster than normal, and/or a misfire when in gear. It is possible that the sensor is failing and needs to be replaced if you encounter any of these signs. They are cheap and easy-to-find particularly in the case of an Bosch unit like ours. Alternatively, GM's version of this part would be an option.
5. Tachometer
A malfunctioning engine speed sensor could be a cause for many issues with your car. It is a crucial part of your Audi's transmission, as it sends information to the ECU about how fast or slow the car's crankshaft is spinning. This sensor can cause the transmission to malfunction and other car components to be affected.
The G5 engine sensor is located at the edge of the transmission, over the flywheel ring. It sends a signal via gray wire to ECU pin T55/49. The ECU utilizes this signal to control the flow of fuel and boost as well as timig. It also relays it to spare audi key cost the G5 Tachometer in instrument cluster. You can check 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 on pin T6a/1 (trace [79trace [79]) and between T6a/1 and the instrument cluster pin audi spare key replacement T26a/12. You should see around 1000 ohms of resistance between those two pins. This is a typical part across the Audi 80, 100, 200, UrS and RS2 range from 1985 MC through the 1997 UrS AAN check here and 1995 RS2 ADU, so the best ones might be availble in wrecking yards.