How to Replace an Audi G28 Engine Speed Sensor
Charles the Humble Technician teaches you how to replace the G28 Engine Speed Sensor. This sensor is situated near the transmission's edge just above the flywheel gear. It sends a message to the ECU via a grey wire T55/49, then to the tachometer on the instrument cluster.
1. Engine Speed Sensor
The grey wire is located at the edges of the transmission, directly above the flywheel ring. The sensor transmits an electrical signal through the grey wire to pin T55/49. The ECU uses this information to control fuel and boost. It also sends a signal to the G5 tachometer in 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 where the camshaft lies so that it can activate the spark and injectors.
If this sensor fails, the ECU will display 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 won't appear on its own without additional information from other sensors (G4 and G40).
Testing is a bit challenging because there are two connector pins, and they have different functions however the best way to test it is by measuring resistance between the sensor and the ECU. When the sensor is fully functional, it should read approximately 1000 ohms. Check for evidence of coolant or oil in the connector bay if there are issues with this part.
2. Injectors
Yesterday, when i was accelerating to the fullest speed from highway paytoll, i experienced an abrupt drop in power as if the engine was running out of gas or injectors are not firing at all. This morning i pull out the spark plugs, 3 were drenched with gazoline the fourth was dry. I placed a tissue over each injector hole and when I start the engine without sparks, the 3 with gazoline jump right out. The 4th one remains closed. I tested the ground connection of ECU pins 14,30 and 48/55. I got zero ohm. I'm assuming that the issue is elsewhere.
I also tried to reset the PID without success. The car will start when the G28 is disconnected, but it runs fine with the G28 plugged in. However the intermittent misfire issue persists at higher RPM. The coolant sensor (G62) even if it is not plugged in, shows an ice temperature of -49c. I also noticed that the oil gauge in the cockpit shows 2 bars when the actual pressure is zero.
I don't know what to do. I believe that I've ruled everything else out. But i am afraid I might have missed something. Let me know should you have any suggestions! TIA!
3. Fuel Pump
The fuel pump in the g28 gets a signal from the RPM sensor. The GM-style transmitter is similar to the G4 sender and both work on the 80,100,200, UrS, and RS2 vehicles. You can easily find the spare in a salvage shop or a parts store. It is simple to test them - put your DMM in resistance mode and measure between pins 1 (with the bump on the connector's side up) and 2 (2nd from left on the black connector's side). They must be infinite Ohms.
4. ECU
The ECU of our 20vt turbo (3B AAN ABY) engines requires to be aware of the speed and position of the crankshaft to make decisions regarding fuel injector timing, more info etc. To accomplish check here this, it makes use of a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If you have a problem with either one of these, the diagnostic scanner will show codes that could cause an engine shutdown.
The signs of a failed G28 sensor include an inaccurate rev counter for the gearbox, gears shifting quicker than normal and/or misfiring when you are in gear. It is probable that your sensor is failing and requires to be replaced if you experience any of these signs. get more info They are cheap and easy-to-find especially if they're an Bosch unit like ours. Alternately, the GM version of this unit is also a great option.
5. Tachometer
A malfunctioning engine speed sensor could be a cause for a slew of problems in your car. It's a vital component of the Audi's transmission since it relays information to the ECU about how the car's crankshaft is rotating. This sensor can cause the transmission to malfunction and other components of the car to be affected.
The G5 engine sensor is located at the outskirts of the transmission, just above the flywheel ring. It transmits signals via a gray wire to the ECU pin T55/49. The ECU uses this signal to control fuel and website boost, and also to timigrate. It also transmits it to the G5 Tachometer inside the instrument cluster. You can check the sensor for any failure by checking the continuity between it and the tachometer. You can also check continuity between ECU pin T55/49 and the instrument cluster connection via pin T6a/1 website (trace [79trace [79]) as well as between T6a/1, and the instrument cluster pin T26a/12. You should see approximately 1000 ohms resistance between those points. This is a typical component across the Audi 80 100 200, UrS and RS2 range from 1985 MC to the 1997 UrS AAN and 1995 RS2 ADU. Good ones could be available in wrecking yards.