How to Replace an Audi G28 Engine Speed Sensor
Charles the Humble Technician shows you how to replace the G28 Engine Speed Sensor. This sensor is located on the outside of the transmission over the flywheel gear. It transmits a signal to the ECU via an uncolored wire T55/49, then to the tachometer located on the instrument cluster.
1. Engine Speed Sensor
The sensor is located at the edge of the transmission just above the flywheel ring gear, the G28 Engine Speed Sensor sends an electrical signal to ECU pin T55/49 through a grey wire. The ECU then utilizes this information to regulate fuel, timig and boost. It also sends signals to the G5 tachometer in the instrument cluster.
The sensor is used to link with the G40 Camshaft position Sensor. The ecu must be aware when the crankshaft is TDC and the location of the camshaft so it can trigger spark and injectors accordingly.
If this sensor fails, the ECU will show an error code P00160 which indicates that the Crank Shaft and Intake Camshaft are out of sync and possibly indicating the chain stretching or a jump link on the upper chain of timing. However, the error code won't appear on its own, without additional information from other sensors (G4 and G40).
Testing can be a bit difficult as there are two different pins for the connector and they have different functions but the best method of testing it is by measuring resistance between the sensor and the ECU. When the sensor is operational, it should be reading about 1000 ohms. If you are having problems with this part, check for signs of oil or coolant in the connector bay.
2. Injectors
Yesterday, when accelerating from highway paytoll at a high speed I noticed a significant reduction in power. It was like the engine had run out of gas. Or my injectors weren't firing. In the morning, i removed the spark plugs, 3 were drenched in gazoline, the fourth one was dry. I placed a tissue over each injector hole, and when I start the engine with no sparks, the ones with gazoline jump right out. The 4th one stays closed. I tested the ground connection of ECU pins 14,30, and 48/55. I got 0ohm. So i assume the problem is somewhere else.
I also tried to reset the PID with no success. The car is able to start when the G28 is disconnected and is running fine when it is connected however it has intermittent misfire issues at higher RPM. The coolant sensor (G62), even when unplugged, still shows an ice temperature of -49c. I also noticed that the oil pressure gauge more info in the cockpit is showing 2 bar when the actual pressure is 0.0 when i rev the engine.
I'm not sure what to do. I feel like i've pretty much all other possibilities out. I'm afraid i may have missed something. If anyone has suggestions, please chime in! TIA!
3. Fuel Pump
The fuel pump in the g28 receives a signal from the RPM sensor. The GM-style sensor is identical to the G4 and audi a3 key replacement near me both function in the 80, 100 200, UrS and RS2 cars so you can easily find one at a junkyard or from a parts store. It is simple to test them - just switch your DMM into resistance mode and measure the distance between pins 1 and 2 (with the bump on the more info connector's edge facing up). They must be infinite Ohms.
4. ECU
Our 20vt turbo (3B AAN, ABY and ADU) engines have an ECU that must know the position and speed of the crankshaft in order to make a decision about fuel injector timing etc. To do this, it makes use of a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If you are experiencing issues with either one of these, the diagnostic scanner will show codes that could lead to the engine shutting down.
Some of the signs of a malfunctioning G28 sensor include an inaccurate gearbox rev counter, gears shifting quicker than normal, and/or a misfire when you are in gear. If you experience any of these problems, it is likely audi spare key replacement that your sensor is failing and should be replaced. The good thing is that they are very affordable and readily available particularly in the case of an Bosch sensor, which is what we have. Alternatively, the GM version of this part is also a good choice.
5. Tachometer
A malfunctioning engine speed sensor could be the reason behind numerous issues in your car. It's a vital component of your Audi's transmission, as it sends information to the ECU about how fast or slow the vehicle's crankshaft is turning. If this sensor fails, it can cause problems for the transmission as well as the rest of the car's components.
The G5 engine speed sensor is located on the outside of the transmission above the flywheel ring gear. It transmits a signal to the ECU at pin T55/49 via an uncolored wire. The ECU utilizes this signal to control the flow of fuel and boost and also to timigrate. It also relays it to the G5 Tachometer inside the instrument cluster. You can test for sensor failure by examining the continuity of the sensor to the tachometer. Additionally, you can check continuity between pin T55/49 of the ECU and pin T6a/1 of the instrument cluster (trace [79trace [79]) and between pin T6a/1 and pin T26a/12. There should be the resistance to be around 1000 ohms between these two points. This is a common feature across the Audi 80-100-200-RS2 model, ranging from the 1985 MC up to the 1997 UrS An and 1995 RS2 website Du So, you may find some good ones in wrecking yards.