How to Replace an Audi G28 Engine Speed Sensor
Charles the Humble Technician teaches you how to replace the G28 Engine Speed Sensor. The sensor is located near the edges of the transmission just above the flywheel ring gear. It transmits a signal to the ECU via the grey wire (T55/49) which is then sent to the tachometer within the instrument cluster.
1. Engine Speed Sensor
Located on the edge of the transmission above the flywheel ring gear the G28 Engine Speed Sensor sends a signal to ECU pin T55/49 via a grey wire. The ECU then uses this information to control fuel, timig and boost. It also sends signals to the G5 tachometer inside the instrument cluster.
The sensor is used as a reference to correlate 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 start spark and injectors in the right way.
If this sensor fails the ECU will throw the P00160 error, which means the Crank Shaft and Intake Camshaft are not in sync, possibly indicating chain stretch or a jumped link on the upper chain of timing. However the code will not appear on its own without additional information from other sensors (G4 and G40).
Testing can be a bit difficult as there are two different connector pins and they have different functions but the most effective way to test it is to measure resistance between the sensor and the ECU. It should read approximately 1000 ohms when it is operating at its maximum. If you are having problems with this sensor, look for signs of coolant or oil in the connector bay.
2. Injectors
Yesterday, when accelerating from highway paytoll at maximum speed I noticed a significant reduction in power. It was as if the engine was running out of gas. Or, my injectors were not firing. In the morning, i removed the spark plugs, 3 were drenched in gazoline, the 4th one was dry. When I start the engine with no sparks i put tissue on the top of each of the injector holes and the 3 drenched with gazoline pop out, but the 4th stay shut. I checked the ground connection of ECU pins 14,30 and 48/55. I got 0ohm. Therefore, i think the issue is somewhere else.
I also tried to audi a4 key replacement reset the PID but without success. The car can start when the G28 is not plugged in and it runs perfectly when it is plugged in however it has intermittent misfire issues at higher RPM. The coolant sensor (G62) even when unplugged, still shows an ice temperature of -49c. Also, i noticed that the gauge for oil pressure 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 believe that I've eliminated everything else. I'm afraid i may have missed something. If anyone has any ideas please share them! TIA!
3. Fuel Pump
The fuel pump in the g28 receives signals from the RPM sensor. The GM-style sender is the same as the G4 and they both work in the 80 100, 200, UrS and RS2 cars which is why you can easily locate one at a junkyard or in a local parts store. It is easy to test them - just put your DMM into resistance mode and determine the distance between pins 1 and 2 (with the bump on the 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 needs to know the position and speed of the crankshaft in order to make a decision about timing of the fuel injector, for example. To do this, it makes use of a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If you encounter a problem with either one of these, the diagnostic scanner will read more display codes that could cause the engine shutting down.
A failing G28 sensor can cause an inaccurate gearbox speed counter or a gearbox that shifts faster than normal, and/or a misfire in gear. It is possible that the sensor is failing and requires to be replaced if you experience any of these signs. They're more info cheap and easy to find particularly when they're a Bosch sensor like ours. Alternately, GM's version this component is an option.
5. Tachometer
A malfunctioning engine sensor can cause a number of problems within your vehicle. check here It is a crucial part of the Audi's transmission as it sends information to the ECU about how fast or slow the car's crankshaft is turning. This sensor could cause the transmission to malfunction and other car components to be affected.
The G5 engine speed sensor is located at the outside of the transmission more info 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 checking continuity from 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. You should detect a resistance of approximately 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 Du So, you may find good ones in wrecking yards.