The No. #1 Question Everybody Working In Audi G28 Should Be Able To Answer
The No. #1 Question Everybody Working In Audi G28 Should Be Able To Answer
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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 situated near the edges of the transmission just above the flywheel ring gear. It sends a message to the ECU through the grey wire T55/49 and then to the tachometer located on the instrument cluster.
1. Engine Speed Sensor
The grey wire is located at the edges of the transmission, above the flywheel ring. The sensor transmits an electrical signal through the grey wire to pin T55/49. The ECU then utilizes this information to regulate the flow of fuel, timig and boost. It also sends a signal to the G5 tachometer in the instrument cluster.
The sensor is used to connect the G40 Camshaft position Sensor. The ecu needs to know when the crankshaft is TDC and where the camshaft is so it can activate spark and injectors according to the situation.
If this sensor fails, the ECU will throw a P00160 code which means the Crank Shaft and Intake Camshaft aren't in sync, possibly indicating chain stretch or a jumped link on the upper chain of timing. However the code will not be displayed on its own without additional information from other sensors (G4 and G40).
It's a bit tricky to test since there are different pins on the connector and each one has different functions. The best way to do it is by measuring the resistance between the ECU and the sensor. When the sensor is fully operational, it should read about 1000 ohms. If you're experiencing issues with this component, look for evidence of coolant or oil in the connector bay.
2. Injectors
Yesterday, when i was accelerating to the fullest speed from highway paytoll, I experienced massive power loss like the engine is running out of gas or the injectors are not firing anymore. This morning i pull out the spark plugs, 3 were soaked with gazoline and the fourth was dry. I put tissue over each injector hole, and when i turn the engine on without sparks, the ones with gazoline jump right out. The fourth one remains closed. I tested the ground connection on ECU pins 14/55,30/55 and 48/55 I get zero ohm. So i assume the problem is elsewhere.
I also tried to reset the PID without success. The car will start when the G28 is unplugged, and it works fine when the G28 plugged in. However, the intermittent misfire problem continues to occur at higher RPM. The coolant sensor (G62), even when unplugged, still shows a temperature of -49c. Also i noticed that the oil pressure gauge in the cockpit shows 2 bar when the actual pressure is 0.0 if i crank up the engine.
I'm not sure what to do, but i think i've pretty much completely ruled out all other possibilities. I'm concerned that i may have missed something. If anyone has any suggestions, please chime in! TIA!
3. Fuel Pump
The fuel pump in the g28 receives signals from the RPM sensor. The GM-style sender is identical to the G4 and both are used in the 80, 100, 200, UrS and RS2 cars which is why you can easily locate one at a salvage yard or from a parts store. It is simple to test them - put your DMM in resistance mode and take measurements between pins 1 (with click here the bump on the connector's end up) and 2 (2nd from the left on the read more black connector's side). They must be infinite ohms.
4. ECU
Our 20vt turbo (3B AAN, ABY and ADU) engines have an ECU that needs to be aware of the speed and position of the crankshaft in order to make a decision about fuel injector timing etc. To do this, it uses a Crank Position Sensor (G4) and an replacement key for audi a4 Engine Speed Sensor (G28). If either of these go bad you will get codes on the diagnostic scanner which can cause the engine to shut down.
Some of the signs of a failed G28 sensor include an inaccurate gearbox rev counter and gears that shift faster than normal and/or a misfire when you're in gear. If you are experiencing any of these problems, it is most likely that your sensor is deteriorating and requires replacement. They're cheap and easy to find, especially if they're an Bosch model like ours. Alternatively, the GM version of this part is also a great option.
5. Tachometer
A damaged engine sensor could cause a myriad of issues in your car. It is an important part of the transmission in your Audi since it sends information to the ECU on how fast or slow the engine is turning. This sensor can cause the transmission to fail and other components in the car to be affected.
The G5 here engine sensor is located near the edge of the transmission, just above the flywheel ring. It transmits an electrical signal through gray wire to ECU pin T55/49. The ECU uses this signal to control the amount of fuel and boost, as well as timig. It also relays it to the G5 Tachometer in instrument cluster. You can determine if the sensor is in failure by examining the continuity from the sensor here to the tachometer. Also, you can check 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. It should show around 1000 ohms of resistance between those points. This is a common feature across the Audi 80-100-200-RS2 series, starting from the 1985 MC all the way up to the 1997 UrS AN and 1995 RS2 DU, so you might find some good ones in wrecking yards.