How to Replace an Audi G28 Engine Speed Sensor
Charles the Humble Technician shows how to replace the G28 Engine Speed Sensor. This sensor is situated near the transmission's edge over the flywheel gear. It sends a signal to the ECU via a grey wire (T55/49), then to the tachometer located in 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 through the grey wire. The ECU then utilizes this information to regulate the flow of fuel, timig and boost. It also sends an alert to the G5 Tachometer located in the instrument cluster.
The sensor is used to connect the G40 Camshaft position Sensor. The ecu must be aware when the crankshaft is TDC and where the camshaft is located so that it can activate spark and injectors according to the situation.
If this sensor fails when it fails, the ECU will display a P00160 error code. This indicates that the Crank Shaft is not in line with the Intake Camshaft. It could also indicate an issue with the chain or a jumped chain link in the upper chain. The code won't show without the additional information provided by other sensors (G4 or G40).
Testing can be a bit difficult as there are two different connector pins, and they perform different functions however the best way to test it is to measure the resistance between the sensor and the ECU. If the sensor is functional, it should read around 1000 ohms. If you are having problems with this sensor, look for signs of oil or coolant in the connector bay.
2. Injectors
Yesterday, while accelerating at full speed from the highway paytoll, I experienced an abrupt drop in power like the engine is out of gas or the injectors aren't firing anymore. In the morning, i removed the spark plugs. Three were soaked with gazoline and the 4th one 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 right out. The 4th one remains shut. I checked the ground connection on ECU pins 14/55,30/55 and 48/55 i get zero ohm. I assume that the problem is somewhere else.
I also tried to reset the PID with no success. The car website will start when the G28 is disconnected, but it works fine when the G28 plugged in. However, the intermittent misfire problem still occurs at higher RPM. The coolant temperature sensor (G62) shows the wrong temperature of that is -49c even after unplugging it. I also noticed that the oil gauge in the cockpit shows 2 bar while the actual pressure is zero.
I'm not sure what to do, as i think i've pretty much completely ruled out all other possibilities. I'm concerned that i may have missed something. Please let me know If you have any suggestions! TIA!
3. Fuel Pump
The fuel pump in the g28 can be activated by a signal by the RPM sensor. The GM-style transmitter is identical to the G4 sender and both work on the 80,100,200, UrS, and RS2 vehicles. You can easily locate an extra in a wrecking shop or a parts store. It is simple to test them - put your DMM in resistance mode and measure the resistance between pins 1 (with the bump on the connector end up) and 2 (2nd from left on the black connector's end). They should be infinite Ohms.
4. ECU
The ECU of our 20vt turbo (3B AAN ABY ADU) engines needs to know both the position and speed of the crankshaft to determine timing of the fuel injector, etc. To accomplish this, it makes use of a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If either of these goes wrong, you will receive codes on the diagnostic scanner that could cause engine shut lost audi keys down.
A damaged G28 sensor can cause an inaccurate speed counter for your gearbox, a gearbox that shifts more quickly than normal, or a misfire in the gear. It is possible that the sensor is failing and requires to be replaced if you encounter any of these signs. They're inexpensive and easy to locate, especially when they're a Bosch sensor like ours. If you prefer, GM's version of this component is a good option.
5. Tachometer
A malfunctioning engine sensor can cause a variety of issues in your car. It's an essential component of the transmission of your Audi since it sends information to the ECU regarding read more how fast or slowly the car's engine is turning. This sensor could cause the transmission audi a1 keys to malfunction and other car components to be affected.
The G5 engine sensor is located at the outskirts of the transmission, just above the flywheel ring. It sends a signal via a gray wire to the ECU pin T55/49. The ECU utilizes this signal to control fuel and boost, and also timig. It also sends it to the G5 Tachometer inside the instrument cluster. You can check the sensor for any failure by audi a1 key checking the continuity between it and the tachometer, between the ECU pin T55/49 and the instrument cluster connection to pin T6a/1 (trace [79trace [79]) as well as between T6a/1, and the instrument cluster pin T26a/12. There should be a resistance of approximately 1000 ohms between these points. This part is common across the Audi 80-100-200-RS2 range, from the 1985 MC up to the 1997 UrS AN and 1995 RS2 Du So, you may find them in wrecking yards.