Audi G28: The Good, The Bad, And The Ugly
Audi G28: The Good, The Bad, And The Ugly
Blog Article
How to Replace an Audi G28 Engine Speed Sensor
Charles the Humble Technician teaches how to replace the G28 Engine Speed Sensor. The sensor is located on the outside of the transmission, above the flywheel gear. It sends a signal to the ECU via a grey wire (T55/49), then to the tachometer within the instrument cluster.
1. Engine Speed Sensor
The grey wire is located on the edge of transmission, directly above the flywheel ring. The sensor sends 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 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 the location of the camshaft so it can activate spark and injectors according to the situation.
If this sensor fails the ECU will display the P00160 error, which means the Crank Shaft and Intake Camshaft aren't in sync and possibly indicating the chain stretching or a jump link on the upper timing chain. However, the code won't appear on its own, without additional information from other sensors (G4 and G40).
It's a bit tricky to test because there are several connector pins, and each one has different functions. The most effective method to test it is by measuring the resistance between the ECU and the sensor. If the sensor is operational, it should read approximately 1000 ohms. If you're having issues with this sensor, look for evidence of oil or coolant in the connector bay.
2. Injectors
Yesterday, when accelerating from highway paytoll at maximum speed I noticed a significant drop in power. It was as if the engine was running out of gas. Or my injectors were not firing. I pulled out the spark plugs this morning, three were drenched in gasoline and the 4th was dry. I put tissue over each injector hole, and when i turn the engine on without sparks, the 3 with gazoline jump right out. The fourth one remains closed. I tested the ground connection on ECU pins 14/55, 30/55 and 48/55. I get 0ohm. I think the issue is somewhere else.
I also tried to reset the PID with no success. The car will start if the G28 is disconnected and is running fine when it is plugged in, but still is experiencing intermittent misfires at higher RPM. The coolant sensor (G62), even if it is not check here plugged in, shows an ice temperature of -49c. Also, i noticed that the oil pressure gauge in the cockpit is showing 2 bar when the actual pressure is 0.0 if i crank up the engine.
I'm not sure what to do. I feel like i've pretty much eliminated everything else. I'm check here concerned that i here may 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 sent 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 find an extra in a wrecking shop or parts store. It is easy to test them - simply switch your DMM into resistance mode and measure the distance between pins 1 and 2 (with the bump at the connector end facing up). They must be infinite Ohms.
4. ECU
Our 20vt turbo (3B AAN, ABY, and ADU) engines are equipped with an ECU that must be aware of the speed and position of the crankshaft to make decisions regarding timing of the fuel injector, for example. To do this, it utilizes a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If either of these sensors go bad you will get codes on the diagnostic scanner which can lead to engine shutdown.
The signs of a failing G28 sensor are an inaccurate rev counter in the gearbox and gears that shift faster than normal, and/or a misfire when you are in gear. If you experience any of these problems, it is most likely that your sensor is failing and requires replacement. They're cheap and easy to find, especially if they're an Bosch sensor like ours. If you prefer, GM's version of this part would be an excellent choice.
5. Tachometer
A failing engine speed sensor could be the reason behind a slew of problems in your vehicle. It's an essential component of your Audi's transmission, since it relays information to the ECU about how the car's crankshaft is spinning. This sensor can cause the transmission to malfunction and other car components to be affected.
The G5 engine speed sensor is situated on the edge of the transmission above the flywheel ring gear and transmits a signal to the ECU at pin T55/49, via an uncolored wire. The ECU utilizes this signal to control the flow of fuel and boost as well as timig. It also relays it to the G5 Tachometer located in the instrument cluster. You can check for sensor failure by examining the continuity from the sensor to the tachometer. Additionally, you can verify continuity between pin T55/49 of the ECU and pin T6a/1 of the instrument cluster (trace click here [79trace [79]), and between pin T6a/1 as well as pin T26a/12. You should observe approximately 1000 ohms of resistance between these two points. This part is common across the Audi 80-100-200-RS2 series, starting from the 1985 MC all the way up to the 1997 UrS AN and the 1995 RS2 Du So, website you may find some good ones in wrecking yards.