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 situated on the edge of the transmission, above the flywheel ring gear. It sends a message to the ECU through the grey wire T55/49 and then to the tachometer on the instrument cluster.
1. Engine Speed Sensor
The grey wire is located on the edge of transmission, directly above the flywheel ring. The sensor transmits a signal via the grey wire to pin T55/49. The ECU utilizes this information to control fuel and boost. It also sends an indication to the G5 Tachometer located in the instrument cluster.
The sensor is used to connect with the G40 Camshaft position Sensor. The ecu needs to know when the crankshaft is TDC and where the camshaft is so it can activate spark and injectors accordingly.
If this sensor fails to function, the ECU will display a P00160 error code. This means that the Crank Shaft is not in sync with the Intake Camshaft. It could also indicate a chain stretch or a jumped chain link in the upper chain of timing. However, the code won't be displayed on its own without additional information from other sensors (G4 and G40).
It can be a bit difficult to test because there are various pins on the connector and each one has different functions. The best method for doing this is by measuring the resistance between the ECU and the sensor. It should read approximately 1000 ohms when the sensor is at full operation. If you're experiencing issues with this component, look for evidence of coolant or oil in the connector bay.
2. Injectors
Yesterday, while accelerating from the highway paytoll at a high speed I noticed a significant drop in power. It was like the engine had run out of gas. Or, my injectors were not firing. I took out the spark plugs this morning, 3 were soaked with gasoline and the fourth was dry. When i crank the engine without sparks i put tissue on top of each injector hole and the 3 drenched with gazoline pop out, but the 4th stays shut. I checked the ground connection of ECU pins 14,30 and 48/55. I got 0ohm. I assume that the problem is elsewhere.
I also tried to reset the PID with no success. The car is able to start when the G28 is not plugged in and runs fine when it is connected however it has intermittent misfire issues at higher RPM. The coolant sensor (G62), even when it is unplugged, shows a temperature of -49c. I also noticed that the oil gauge in the cockpit shows 2 bars when the actual pressure is zero.
I'm not certain what to do, i believe that i've ruled out everything else. But i'm worried that I might have missed something. If anyone has any ideas please share them! TIA!
3. Fuel Pump
The fuel pump on the g28 is activated by a signal from the RPM sensor. The GM-style transmitter is identical to the G4 sender, and both operate on the 80,100,200, UrS, and RS2 vehicles. You can easily find the spare in a salvage shop or a parts store. It is simple 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 upwards). They should be infinite Ohms.
4. ECU
The ECU in our 20vt turbo (3B AAN ABY ADU) engines must know both the speed and position of the crankshaft in order to make a decision about timing of fuel injectors, etc. It uses a Crank Position Sensor G4 and an Engine Speed Sensor G28 to accomplish this. If you are experiencing check here issues with either of these, the diagnostic scanner will display codes that could cause an engine shutdown.
A damaged G28 sensor could result in an inaccurate speed counter for your gearbox or a gearbox that shifts more quickly than normal, or an unfire when in the gear. It is probable that the sensor is failing and requires to be replaced if you experience any of these symptoms. They are cheap and easy-to-find especially if they're an Bosch model like ours. You can also choose the GM version of this component is also a good option.
5. Tachometer
A damaged engine sensor could cause a myriad of website issues within your vehicle. It's an essential component of the transmission of your Audi since click here it sends information to the ECU regarding how fast or slowly the car's engine is spinning. This sensor can cause the transmission to fail and other components in the car to be affected.
The G5 engine sensor is here located at the outskirts of the transmission, over the flywheel ring. It sends signals via a gray wire to the ECU pin T55/49. The ECU then processes this signal to regulate fuel, timig, and boost, and also transmitting it to the G5 tachometer inside the instrument cluster. You can test the sensor check here for failure by checking continuity between it and the tachometer. You can also check continuity between ECU pin T55/49 and the instrument cluster connection via pin T6a/1 (trace [79trace [79]) and between pin T6a/1 and the instrument cluster pin T26a/12. You should detect the resistance to be around 1000 ohms between these two points. This is a common feature across the Audi 80-100-200-RS2 series, starting beginning with the 1985 MC and up to the 1997 UrS AN and the 1995 RS2 DU, so you might find good ones in wrecking yards.