"Ask Me Anything": Ten Answers To Your Questions About Audi G28
"Ask Me Anything": Ten Answers To Your Questions About Audi G28
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How to Replace an Audi G28 Engine Speed Sensor
Charles the Humble Technician shows you how to replace the G28 Engine Speed Sensor. The sensor is located at the top of the transmission, above the flywheel ring gear. It transmits a signal the ECU via an uncolored wire (T55/49), then to the tachometer located in the instrument cluster.
1. Engine Speed Sensor
It is located on the outside of the transmission, above the flywheel ring gear G28 Engine Speed Sensor sends an electrical signal to ECU pin T55/49 using the grey wire. The ECU then uses this information to control fuel, timig and boost. It also sends an indication to the G5 Tachometer in instrument cluster.
The sensor is used to connect the G40 Camshaft position Sensor. The ecu has to know when the crankshaft has reached TDC, and where the camshaft lies so that it can activate the spark and injectors.
If this sensor fails, the ECU will display a P00160 error code. This means that the Crank Shaft is not in line with the Intake Camshaft. It could also be a sign of the possibility of a chain stretch or jump in the chain link of the upper chain of timing. However, the code won't appear on its own, without additional information from other sensors (G4 and G40).
Testing is a bit tricky since there are two connector pins and they perform different functions however the best way to test it is to measure resistance between the sensor and the ECU. It should read approximately 1000 ohms if the sensor is operating at its maximum. If you are having problems with this sensor, look for signs of oil or coolant in the connector bay.
2. Injectors
Yesterday, when i was accelerating to the fullest speed from highway paytoll, i experienced a big cut in power like the engine is running out of gas or injectors aren't firing any more. This morning i pull out the spark plugs. Three were drenched with gazoline the fourth 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 4th one stays closed. I tested the ground connection of ECU pins 14,30, and 48/55. I found 0ohm. I assume that the problem is elsewhere.
I also tried to reset PID without success. The car can start when the G28 is unplugged and runs fine when it is plugged in but it still has the intermittent misfire issue at higher RPM. The temperature sensor for coolant (G62) shows the wrong temperature value of click here that is -49c even after unplugging it. Also, i noticed that the gauge for oil pressure in the cockpit is showing 2 bar while the actual pressure is 0.0 if i crank up the engine.
I'm not sure what to do, i think i've pretty much eliminated everything else. But i'm worried that i might have audi a5 replacement key missed something. Please let me know if you have any ideas! TIA!
3. Fuel Pump
The fuel pump in the g28 is activated by a signal sent 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 more info can easily locate one at a junkyard or from a parts store. It is easy to test them: simply switch your DMM into resistance mode and test the distance between pins 1 and 2 (with the bump on the connector's edge facing upwards). They should be infinite Ohms.
4. ECU
The ECU of our 20vt audi spare key turbo (3B AAN ABY) engines needs to know both the position and speed the crankshaft to make decisions regarding timing of fuel injectors, etc. It uses a Crank Position Sensor G4 and an Engine Speed Sensor G28 to accomplish this. If either of these goes badly, you will see codes on the diagnostic scanner that can cause the engine to shut down.
A damaged G28 sensor could cause an inaccurate speed counter for the gearbox and a gearbox which shifts faster than normal, or a misfire while in the gear. If you have any of these problems, it is likely your sensor is failing and should be replaced. The good thing is that they are very cheap and easily accessible particularly in the case of a Bosch sensor, like ours. Alternately, GM's version this part is a good option.
5. Tachometer
A failing engine speed sensor could be the cause of a slew of problems in your vehicle. It's an essential component of the transmission in your Audi, as it transmits information to the ECU on how fast or slow the engine is turning. If this sensor fails, it can disrupt the performance of the transmission, as well as the rest of the car's components.
The G5 engine sensor is located at the outskirts of the transmission, just above the flywheel ring. It sends an electrical signal through an uncolored wire to the ECU pin T55/49. The ECU utilizes this signal to control the flow of fuel and boost as well as timig. It also transmits it to the G5 Tachometer in instrument cluster. You can check the audi a4 key replacement sensor for failure by checking 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. You should see an average resistance of 1000 ohms in these areas. This is a common part that is found 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 could be available in wrecking yards.