What NOT To Do In The Audi G28 Industry
How to Replace an Audi G28 Engine Speed Sensor
In this video, Charles the Humble Mechanic shows how to replace the G28 engine speed sensor. This sensor is located at the edge of transmission just above the flywheel gear. It transmits a signal to the ECU through a grey wire T55/49, then to the tachometer on the instrument cluster.
1. Engine Speed Sensor
Located on the edge of the transmission, above the flywheel ring gear G28 Engine Speed Sensor sends signals to ECU pin T55/49 using an uncolored wire. The ECU uses this information to control boost and fuel. It also sends an indication to the G5 Tachometer located in the instrument cluster.
The sensor is used as a reference point to connect with the G40 Camshaft Position Sensor. The ecu must be aware of when the crankshaft has reached TDC and also where the camshaft lies to trigger the spark and injectors.
If this sensor fails when it fails, the ECU will display a P00160 error message. 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. However, the code won't appear on its own without additional information from other sensors (G4 and G40).
Testing can be a bit difficult as there are two different pins for the connector and they have different functions but the best method to test it is to measure the resistance between the sensor and the ECU. When the sensor is operational, it should be reading about 1000 ohms. If you are having problems with this part, check for evidence of oil or coolant in the connector bay.
2. Injectors
Yesterday, when i was accelerating to the fullest speed from highway paytoll, I experienced an abrupt drop in power as if the engine was running out of gas or injectors are not firing at all. This morning i pull out the spark plugs, 3 were soaked with gazoline and the 4th one was dry. When I crank the engine, there are no 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 one stays closed. I checked the ground connection of ECU pins 14,30 and 48/55. I got zero ohm. Therefore, i think the issue is elsewhere.
I also tried to reset the PID without success. dig this will start when the G28 is disconnected, but it runs fine with the G28 connected. However the intermittent misfire issue still occurs 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 0.
I don't know what to do. I think I've all other possibilities out. I'm worried that i might have missed something. Please let me know if you have any ideas! TIA!
3. Fuel Pump
The fuel pump in the g28 is activated by a signal sent by the RPM sensor. The GM-style sensor is the same as the G4 and they both work in the 80, 100 200, UrS and RS2 cars so you can easily find one at a salvage yard or from a parts store. Testing them is easy - put your DMM in resistance mode and measure the resistance between pins 1 (with the bump on the connector's side up) and 2 (2nd from the left on the black connector's side). They should be infinite Ohms.
4. ECU
The ECU in our 20vt turbo (3B AAN ABY ADU) engines requires to be aware of the position and speed the crankshaft to make decisions regarding timing of the fuel injector, etc. To accomplish this, it utilizes a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If you encounter a problem with either of these sensors, the diagnostic scanner will display the codes that could trigger an engine shutdown.
Some of the signs of a failed G28 sensor are an inaccurate rev counter in the gearbox the gears are shifting faster than normal, and/or a misfire when in gear. If you have any of these issues it is most likely that your sensor is deteriorating and should be replaced. They are cheap and easy-to-find particularly when they're an Bosch unit like ours. Alternatively, the GM version of this component is also a great option.
5. Tachometer
A malfunctioning engine speed sensor could be a cause for many problems in your vehicle. It's a crucial component of the transmission of your Audi because it relays information to the ECU regarding how fast or slowly the engine is turning. If this sensor fails, it can cause problems for the transmission as well as the other car's components.
The G5 engine speed sensor is located at the outside of the transmission above the flywheel ring gear. It sends a signal to the ECU at pin T55/49 through an uncolored wire. The ECU then processes this signal to regulate fuel, timig, and boost, and also transmitting it to the G5 tachometer in the instrument cluster. replacement car key audi can test for sensor failure by examining the continuity of the sensor to the tachometer. Also, you can examine the continuity between pins T55/49 of the ECU and pin T6a/1 of the instrument cluster (trace [79]) and between pin T6a/1 as well as pin T26a/12. You should observe approximately 1000 ohms of resistance between those points. This is a typical component across the Audi 80, 100, 200, UrS and RS2 range from 1985 MC through the 1997 UrS AAN and 1995 RS2 ADU so good parts could be found in wrecking yards.