10 Wrong Answers To Common Audi G28 Questions Do You Know The Correct Answers?
10 Wrong Answers To Common Audi G28 Questions Do You Know The Correct Answers?
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How to Replace an Audi G28 Engine Speed Sensor
In this video, Charles the Humble Mechanic demonstrates how to replace the G28 engine speed sensor. The sensor is located on the outside of the transmission, above the flywheel gear. It sends a signal to the ECU via the grey wire (T55/49) and 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 a signal to ECU pin T55/49 via a grey wire. The ECU then uses this information to control fuel, timig and boost. It also sends an indication to the G5 Tachometer within the instrument cluster.
The sensor is used to link the G40 Camshaft position Sensor. The ecu has to be aware of when the crankshaft has reached TDC and also the location of the camshaft in order to activate 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 and possibly indicating chain stretch or a jumped link on the upper timing chain. However the code will not appear on its own, without additional information from other sensors (G4 and G40).
Testing is a bit challenging because there are two pins for the connector and they serve different purposes but the most effective method of testing it is by measuring resistance between the sensor and the ECU. It should read about 1000 ohms when the sensor is operating at its maximum. If you are having problems with this sensor, look for evidence of oil or coolant in the connector bay.
2. Injectors
Yesterday, when accelerating from highway paytoll at a high speed I noticed a significant decrease in power. It was as if the engine was running 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. When I crank the engine without sparks, I put a piece of tissue on top of each injector hole, the 3 drenched with gazoline pop out, but the 4th one stays closed. I checked the ground connection on ECU pins 14/55,30/55 and 48/55 i get 0ohm. So i assume the problem is car key replacement audi somewhere else.
I also tried to reset PID without success. The car will start when the G28 is unplugged, and it runs fine with the G28 plugged in. However the intermittent misfire issue continues to occur at higher RPM. The temperature sensor for coolant (G62) shows the wrong temperature value of -49c even when i unplug it. I also noticed that the oil pressure gauge in the cockpit shows 2 bar when the actual audi spare key pressure is 0.0 if i crank up the engine.
I'm not certain what to do, i believe that i've ruled out everything else. 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 gets a signal from the RPM sensor. The GM-style transmitter is identical to the G4 and they both work in the 80, 100 200, UrS and check here RS2 cars which is why you can easily locate one at a wrecking yard or in a local parts store. Testing them is easy 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 the left on the black connector's side). They must be infinite Ohms.
4. ECU
The ECU of our 20vt turbo (3B AAN ABY) engines click here must know both the position and speed of the crankshaft to determine timing of the fuel injector, etc. To accomplish this, it makes use of a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If you have a problem with either of these sensors, the diagnostic scanner will show the codes that could trigger an engine shutdown.
The signs of a malfunctioning G28 sensor are an inaccurate rev counter for the gearbox and gears that shift faster than normal and/or a misfire when you are in gear. If you have any of these issues it is most likely that your sensor is failing and needs replacing. They're inexpensive and easy to locate especially when they're an Bosch sensor like ours. If you prefer, GM's version of this component is an option.
5. Tachometer
A faulty engine speed sensor could be a cause for numerous problems in your vehicle. It's an essential component of the Audi's transmission because it communicates to the ECU about how fast or slow the car's crankshaft is turning. This sensor can cause the transmission to fail 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 an uncolored wire. The ECU is then able to process this signal to control fuel, timig, and boost as well as transmitting it to the G5 Tachometer located in the instrument cluster. You can check the sensor for failure by examining the continuity between it and the tachometer. You can also check continuity between ECU pin T55/49 and the instrument cluster connection to pin click here T6a/1 (trace [79trace [79]) and between pin T6a/1 and the instrument cluster pin T26a/12. You should detect a resistance of approximately 1000 ohms between these two points. This is a typical part across the Audi 80, 100 200, UrS and RS2 range from 1985 MC through the 1997 UrS AAN and 1995 RS2 ADU so good parts could be found in wrecking yards.