How to Replace an Audi G28 Engine Speed Sensor
Charles the Humble Technician teaches how to replace the G28 Engine Speed Sensor. The sensor is located on the edge of the transmission, above the flywheel ring gear. It transmits a signal the ECU via an uncolored wire (T55/49), then to the tachometer in the instrument cluster.
1. Engine Speed Sensor
The sensor is located at the edge of the transmission just above the flywheel ring gear G28 Engine Speed Sensor sends a signal to ECU pin T55/49 through a grey wire. The ECU utilizes this information to regulate boost and fuel. It also sends signals to the G5 tachometer inside the instrument cluster.
The sensor is used to connect the G40 Camshaft position Sensor. The ecu needs to know when the crankshaft is TDC and where the camshaft is located so that it can trigger spark and injectors in the right way.
If this sensor fails, the ECU will show a P00160 code which means the Crank Shaft and Intake Camshaft are out of sync, possibly indicating the chain stretching or a jump link on the upper chain of timing. The code won't appear without the additional information provided by other sensors (G4 or G40).
Testing is a bit challenging because there are two connector pins, and they perform different functions but the most effective way to test it is by measuring resistance between the sensor and the ECU. It should read approximately 1000 ohms when the sensor is operating at its maximum. If you're experiencing issues with this part, check for evidence of oil or coolant in the connector bay.
2. Injectors
Yesterday, as i was accelerating off the highway paytoll at maximum speed I noticed a massive decrease in power. It was like the engine was running out of gas. Or my injectors were not firing. This morning i pull out the spark plugs, three were drenched with gazoline the fourth was dry. I placed a tissue over each injector hole and when I turn the engine on without sparks, the 3 with gazoline jump out. The 4th one stays closed. I checked the ground connection of ECU pins 14,30 and 48/55. I got 0ohm. I think the issue is somewhere else.
I also tried to reset the PID but without success. The car will start click here when the G28 is disconnected, but it is running fine with the G28 connected. However the intermittent misfire issue continues to occur 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 bar when the actual pressure is zero.
I don't know what to do. I believe that I've eliminated everything else. I'm concerned that i may have missed something. If anyone has suggestions, please share them! TIA!
3. Fuel Pump
The fuel pump in the g28 can be activated by a signal sent by the RPM sensor. The GM-style sender is identical to 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 - put your DMM in resistance mode and measure between pins 1 (with the bump on the connector's end up) and 2 (2nd from left on the black end of the connector). They should be infinite Ohms.
4. ECU
Our 20vt turbo (3B AAN, ABY, and ADU) engines have an ECU that needs to be aware of the speed and position of the crankshaft to make decisions regarding timing of the fuel injector, for example. It makes use of a Crank Position Sensor G4 and an Engine Speed Sensor G28 to accomplish this. If either of these goes wrong, you will receive codes on the diagnostic scanner that can lead to engine shutdown.
Some of the symptoms of a failing G28 sensor are an inaccurate gearbox rev counter and gears that shift faster than normal, and/or a misfire when you are in gear. It is probable replace audi key that the sensor is failing and needs to be replaced if you encounter any of these signs. The good thing is that they are very affordable and easy to find particularly if you're looking at the Bosch sensor, like ours. Alternately, GM's version this part is an excellent choice.
5. Tachometer
A failing engine sensor could cause a number of problems in your vehicle. It is an important part of the transmission of your Audi because it relays information to the ECU on how fast or slow the engine is spinning. This sensor could cause the transmission to malfunction and other components in the car to be affected.
The G5 engine sensor is located at the edge of the transmission, over the flywheel ring. It sends audi a1 car key a signal via gray wire to ECU pin T55/49. The ECU utilizes this signal to control the flow of fuel and boost as well as timig. It also relays it to the audi lost key G5 Tachometer in instrument cluster. You can test for sensor failure by checking continuity from the sensor to the tachometer. You can also check continuity between pin T55/49 of the ECU and pin T6a/1 of the instrument more info cluster (trace [79trace [79]) and between pin T6a/1 as well as pin T26a/12. There should be 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 some good ones in wrecking yards.