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. This sensor is situated near the transmission's edge, above the flywheel gear. It sends a signal to the ECU via the grey wire (T55/49), then to the tachometer in the instrument cluster.
1. Engine Speed Sensor
The grey wire is located at the edges of the transmission, just above the flywheel ring. The sensor transmits signals through the grey wire to pin T55/49. The ECU then utilizes this information to regulate the flow of fuel, timig and boost. It also sends signals to the G5 tachometer in the instrument cluster.
The sensor is used to connect with the G40 Camshaft position Sensor. The ecu has to know when the crankshaft has reached TDC and also the position of the camshaft, in order to activate the spark and injectors.
If this sensor fails to function, the ECU will display an error code P00160. This means that the Crank Shaft is not in sync with the Intake Camshaft. It could also be a sign of the possibility of a chain stretch or jumped chain link in the upper chain. The code won't show without the additional information provided by other sensors (G4 or G40).
Testing is a bit tricky because there are two pins for the connector and they serve different purposes however the best method of testing it is by measuring resistance between the sensor and the ECU. If the sensor is functional, it should read approximately 1000 ohms. If you're experiencing issues with this component, look for evidence of oil or coolant in the connector bay.
2. Injectors
Yesterday, while accelerating from the highway paytoll at full speed I noticed a massive decrease in power. It was as if the engine was running out of gas. Or my injectors were not firing. I pulled out the spark plugs this morning, three were soaked in gasoline, and the 4th was dry. I put a piece of tissue over each hole in the injector and when i turn the engine on without sparks, the 3 with gazoline jump out. The 4th one remains closed. I tested the ground connection on ECU pins 14/55/30/55/48/55/14/55/48/ i get zero ohm. So i assume the problem is elsewhere.
I also tried to reset the PID without success. The car will start when the G28 is unplugged, and it runs fine with the G28 plugged in. However, the intermittent misfire problem persists at higher RPM. The coolant sensor (G62) even if it is not plugged in, shows temperatures of -49c. I also noticed that the oil pressure gauge in the cockpit is showing 2 bar, whereas the actual pressure is 0.0 when i rev the engine.
I don't know what to do. I feel like i've pretty much ruled everything else out. I'm concerned that i may have missed something. Please let me know should you have any suggestions! TIA!
3. Fuel Pump
The fuel pump in the g28 receives a signal 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 salvage yard or from a parts store. It is simple to test them - simply put your DMM into resistance mode and test the distance between pins 1 and 2 (with the bump at the connector end facing upwards). They should be infinite Ohms.
4. ECU
The ECU in our 20vt turbo (3B AAN ABY) engines needs to know both the position and speed of the crankshaft in order to make a decision about fuel injector timing, etc. It uses a Crank Position Sensor G4 and an Engine Speed Sensor G28 to achieve this. If you are experiencing issues with either of these, the diagnostic scanner will show the codes that could trigger an engine shutdown.
A failing G28 sensor can cause an inaccurate speed counter for the gearbox and a gearbox which shifts more quickly than normal, and/or a misfire while in the gear. It is probable check here that the sensor is failing and requires to be replaced if you notice any of these signs. The good thing is that they are quite affordable and easy to find particularly when you're looking at a Bosch model, which is what we have. If you prefer, GM's version of this component is an option.
5. Tachometer
A failing engine speed sensor could be the reason behind many problems in your car. It's an essential component of the Audi's transmission because it communicates to the ECU about how fast website or slow the here vehicle's crankshaft is rotating. This sensor can cause the transmission to fail and other components in the car to be affected.
The G5 engine speed sensor is located on the edge of the transmission above the flywheel ring gear and sends a signal directly to the ECU at pin T55/49, via an uncolored wire. audi a4 key replacement The ECU uses this signal to regulate the amount of fuel and boost, as well as timig. It also sends it to the G5 Tachometer located in the instrument cluster. You can test for sensor failure by examining the continuity of the sensor to the tachometer. Also, you can examine the continuity between pins 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. There should be a resistance of approximately 1000 ohms in these areas. This is a common component across the Audi 80, 100, 200, UrS and RS2 range from 1985 MC more info until the 1997 UrS AAN and 1995 RS2 ADU. Good ones might be availble in wrecking yards.