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 located on the outside of the transmission, above the flywheel gear. It transmits a signal to the ECU via a grey wire (T55/49) which is then sent to the tachometer in the instrument cluster.
1. Engine Speed Sensor
The grey wire is situated at the edges of the transmission, just above the flywheel ring. The sensor transmits a signal via 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 a signal to the G5 tachometer in the instrument cluster.
The sensor serves as a reference point to connect with the G40 Camshaft Position Sensor. The ecu has to know when the crankshaft reached TDC, and where the camshaft lies so that it can activate the spark and injectors.
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 jump in the chain link of the upper timing chain. The code won't show without the additional information provided by other sensors (G4 or G40).
It can be a bit difficult to test as there are different connector pins, and each one has different functions. The best way to do it is to measure the resistance between the ECU and the sensor. It should read around 1000 ohms when the sensor is operating at its maximum. If you're having issues with this component, look for signs of coolant or oil in the connector bay.
2. Injectors
Yesterday, as i was accelerating off the highway paytoll at a high speed, i noticed a huge reduction in power. It was like the engine was running out of gas. Or, my injectors were not firing. I took out the spark plugs this morning, three were drenched in gasoline and the 4th was dry. When I crank the engine, there are no sparks, I put a piece of tissue on top of each injector hole and the 3 drenched with gazoline leap out, however the 4th stays closed. I tried to test the ground connections of ECU pins 14,30 and 48/55. I got zero ohm. I assume that the problem is elsewhere.
I also tried to reset the PID with no success. The car will start when the G28 is get more info disconnected, but it works fine when the G28 plugged in. However, the intermittent misfire problem persists at higher RPM. The coolant sensor (G62) even when unplugged, still shows an ice temperature of -49c. I also noticed that the oil gauge in the cockpit shows 2 bar while the actual pressure is zero.
I don't know what to do. I think I've all other possibilities out. 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 sent by the RPM sensor. The GM-style transmitter is similar to the G4 sender, and both operate on the 80,100,200, UrS, and RS2 vehicles. It is easy to find a spare in click here a wrecking shop or a parts store. It is simple to test them - simply put your DMM into resistance mode and determine the distance between pins 1 and 2 (with the bump website on the audi replacement keys connector's edge facing up). They should be infinite Ohms.
4. ECU
Our 20vt turbo (3B AAN, ABY, and ADU) engines are equipped with an ECU that needs to be aware of the speed and position of the crankshaft in order to make decisions regarding timing of the fuel injectors, 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, audi a3 key replacement you will receive codes on the diagnostic scanner that could cause engine shut down.
Some of the signs of a failed G28 sensor are an inaccurate rev counter for the gearbox the gears are shifting faster than normal, and/or a misfire when you're in gear. If you have any of these issues, it is most likely that your sensor is deteriorating and should be replaced. They're cheap and easy to find especially in the case of an Bosch model like ours. If you prefer, GM's version of this component is an excellent choice.
5. Tachometer
A damaged engine sensor could cause a myriad of issues within your vehicle. It's an essential component of the transmission in your Audi because it relays information to the ECU regarding how fast or slow the engine of the car is spinning. This sensor can cause the transmission to fail and other components of the car to be affected.
The G5 engine speed sensor is located on the outside of the transmission, above the flywheel ring gear and sends a signal to the ECU at pin T55/49 through a grey wire. The ECU is then able to process the signal to control fuel, timig and boost and then sends it on to the G5 tachometer in the instrument cluster. You can check the sensor 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 to pin T6a/1 (trace [79trace [79]) as well as between T6a/1, and the instrument cluster pin T26a/12. You should see an average resistance of 1000 ohms between these two points. This is a common feature across the Audi 80-100-200-RS2 range, beginning with the 1985 MC and up to the 1997 UrS An and 1995 RS2 DU So, you may find some good ones in wrecking yards.