Audi G28: The Good, The Bad, And The Ugly
Audi G28: The Good, The Bad, And The Ugly
Blog Article
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 situated at the top of the transmission, above the flywheel ring gear. It sends a message to the ECU via the grey wire T55/49 and then to the tachometer located on the instrument cluster.
1. Engine Speed Sensor
The sensor is located at the edge of the transmission, above the flywheel ring gear the G28 Engine Speed Sensor sends an electrical signal to ECU pin T55/49 using the grey wire. The ECU uses this information to control the amount of fuel and boost. It also sends signals to the G5 tachometer inside the instrument cluster.
The sensor is used as a reference point to connect with the G40 Camshaft Position Sensor. The ecu has to know when the crankshaft reached TDC, and where the camshaft lies in order to activate the spark and injectors.
If this sensor fails, the ECU will throw an error code P00160 which indicates that the Crank Shaft and Intake Camshaft are out of sync and possibly indicating chain stretch or a jumped link on the upper chain of timing. The code won't appear without the additional information supplied by other sensors (G4 or G40).
Testing is a bit challenging since there are two connector pins, and they have different functions but the best way to test it is to measure resistance between the sensor and the ECU. It should read around 1000 ohms when the sensor is at full operation. If you're having issues with this part, check for evidence of oil or coolant in the connector bay.
2. Injectors
Yesterday, when accelerating from highway paytoll at maximum speed I noticed a significant drop in power. It was like the engine was running out of gas. Or, my injectors were not firing. I pulled out the spark plugs this morning, 3 were soaked with gasoline and the fourth was dry. I placed a tissue over each hole in the injector and when i turn the engine on without sparks, the 3 that have gazoline pop right out. The 4th one stays shut. I tried to test the ground connections of ECU pins 14,30 and 48/55. I got 0ohm. I assume that the problem is in another location.
I also tried to reset the PID without success. The car will start if the G28 is not plugged in and runs fine when it is plugged in but it still has intermittent misfire issues at higher RPM. The temperature sensor for coolant (G62) shows the wrong temperature of -49c even when i unplug it. Also i noticed that the oil pressure gauge in the cockpit shows 2 bar when the actual pressure is 0.0 if i crank how to open audi car key up the engine.
I'm not certain what to do, i think i've pretty much completely ruled out all other possibilities. I'm afraid i may have missed something. Let me know if you have any ideas! TIA!
3. Fuel Pump
The fuel pump on the g28 is activated by a signal sent from the RPM sensor. The GM-style transmitter functions similarly to the G4 sender, and both operate on the 80,100,200, UrS, and RS2 vehicles. You can easily find a spare in a wrecking shop or parts store. It is simple to test them - simply put your DMM into resistance mode and determine 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 in our 20vt turbo (3B AAN ABY ADU) engines must be aware of the position and speed of the crankshaft to make decisions regarding fuel injector timing, etc. To do this, it utilizes a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If either of these sensors go badly, you will see codes on the diagnostic scanner which could cause engine shut down.
Some of the signs of a failed G28 sensor are an inaccurate rev counter in the gearbox the gears are shifting faster than normal, and/or a misfire when you are in gear. If you experience any of these issues it is most likely that your sensor is going bad and needs replacing. The good news is they are very cheap and readily available particularly if you're looking at the Bosch sensor, which is what ours are. more info Alternately, GM's version this component is an excellent choice.
5. Tachometer
A faulty engine speed sensor could be the reason behind many issues in your vehicle. It's a vital component of the 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 near the edge of the transmission, over the flywheel ring. It sends a signal via an uncolored wire to the ECU pin T55/49. The ECU uses this signal to regulate the amount of fuel and boost, as replacement audi key well as timig. It also relays it to the G5 Tachometer located in the instrument check here cluster. You can test for sensor failure by checking continuity from the sensor 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 as well as pin T26a/12. You should observe approximately 1000 ohms of resistance between those two pins. This is a common part that is found across the Audi 80 100, 200, UrS and how to open audi car key RS2 range from 1985 MC through the 1997 UrS AAN and 1995 RS2 ADU so good ones might be availble in wrecking yards.