20 Inspirational Quotes About Audi G28
How to Replace an Audi G28 Engine Speed Sensor
Charles the Humble Technician shows how to replace the G28 Engine Speed Sensor. The sensor is located at the top of the transmission above the flywheel ring gear. It transmits a signal to the ECU via an uncolored wire (T55/49), then to the tachometer located in the instrument cluster.
1. Engine Speed Sensor
The sensor is located at the edge of the transmission, above the flywheel ring gear G28 Engine Speed Sensor sends a signal to ECU pin T55/49 through the grey wire. The ECU then uses this information to control the boost, fuel, and timig. It also sends an alert to the G5 Tachometer within the instrument cluster.
The sensor serves as a reference to correlate with the G40 Camshaft Position Sensor. The ecu needs to be aware of when the crankshaft has reached TDC and also the position of the camshaft, to trigger the spark and injectors.
If this sensor fails when it fails, the ECU will display an error code P00160. This indicates that the Crank Shaft is out of line with the Intake Camshaft. It could also be a sign of a chain stretch or a jump in the chain link of the upper timing chain. The code won't appear without the additional information provided by other sensors (G4 or G40).
It can be a bit difficult to test as there are various connector pins, and they all have different functions. The best method for doing this is by measuring the resistance between the ECU and the sensor. It should read around 1000 ohms if the sensor is at full operation. If you're experiencing issues with this component, look for signs of coolant or oil 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 running out of gas or the injectors aren't firing at all. I took out the spark plugs this morning, three were drenched in gasoline and the 4th was dry. When I crank the engine without sparks, I put a piece of tissue on the top of each of the injector holes and the 3 that were drenched in gazoline leap out, however the 4th stay shut. I tested the ground connection on ECU pins 14/55/30/55/48/55/14/55/48/ i get 0ohm. So i assume the problem is elsewhere.
I also tried to reset the PID but without success. The car will start 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 temperature sensor for the coolant (G62) shows the wrong temp value that is -49c even after unplugging it. I also noticed that the oil gauge in the cockpit shows 2 bars but the actual pressure is zero.
I don't know what to do. I think I've ruled everything else out. But i am afraid I might have missed something. Let me know should you have any suggestions! TIA!
3. Fuel Pump
The fuel pump in the g28 is activated by a signal from 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 the spare in a salvage shop or parts store. It is simple to test them: simply switch your DMM into resistance mode and test the distance between pins 1 and 2 (with the bump on the connector's edge facing upwards). They must be infinite Ohms.
4. ECU
audi a1 keys (3B, AAN, ABY and ADU) engines are equipped with an ECU that has to know the position and speed of the crankshaft to make decisions regarding timing of the fuel injector, for example. To do this, it uses a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If you have a problem with either of these sensors, the diagnostic scanner will display codes that could lead to an engine shutdown.
A malfunctioning G28 sensor could result in an inaccurate gearbox speed counter and a gearbox which shifts faster than normal, or a misfire while in gear. If you have any of these issues it is likely that your sensor is failing and requires replacement. They're cheap and easy to find particularly in the case of a Bosch unit like ours. Alternately, the GM version of this part is also a good option.
5. Tachometer
A malfunctioning engine speed sensor could be the cause of many issues in your vehicle. It's a crucial component of the transmission in your Audi because it relays information to the ECU about how fast or slowly the engine of the car is spinning. When this sensor fails, it will cause problems for the transmission, as well as the rest of the car's components.
The G5 engine sensor is located at the edge of the transmission, over the flywheel ring. It transmits a signal via gray wire to ECU pin T55/49. The ECU is then able to process this signal to control fuel, timig, and boost as well as sends it on to the G5 Tachometer located in the instrument cluster. You can test the sensor for failure by examining the continuity between it and the tachometer, between the ECU pin T55/49 and the instrument cluster connection to pin T6a/1 (trace [79]) as well as between T6a/1, and the instrument cluster pin T26a/12. It should show around 1000 ohms of resistance between those two pins. 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 1995 RS2 DU So, you may find them in wrecking yards.