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
In this video, Charles the Humble Mechanic demonstrates how to replace the G28 engine speed sensor. This sensor is located at the top of the transmission above the flywheel ring gear. It transmits a signal the ECU via a grey wire (T55/49), then to the tachometer within the instrument cluster.
1. Engine Speed Sensor
The grey wire is situated at the edges of the transmission, just above the flywheel ring. This sensor sends a signal via the grey wire to pin T55/49. The ECU utilizes this information to regulate the amount of fuel 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 must be aware when the crankshaft is TDC and the location of the camshaft so it can trigger spark and injectors accordingly.
If this sensor fails the ECU will show an error code P00160 which indicates that the Crank Shaft and Intake Camshaft are out of sync and could indicate the chain stretching or a jump link on the upper chain of timing. The code won't appear without the additional information supplied by other sensors (G4 or G40).
Testing is a bit tricky since there are two pins for the connector and they have different functions however the best method to test it is by measuring resistance between the sensor and the ECU. It should read approximately 1000 ohms when the sensor is at full operation. 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 full speed, i noticed a huge reduction in power. It was like the engine had run out of gas. Or, my injectors were not firing. This morning i pull out the spark plugs, three were drenched with gazoline the 4th one 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 shut. I checked the ground connection on ECU pins 14/55, 30/55 and 48/55. I get zero Ohm. I assume that the problem is elsewhere.
I also tried to reset the PID but with no luck. The car will start when the G28 is disconnected, but it website is running fine with the G28 connected. However the intermittent misfire issue still occurs at higher RPM. The coolant sensor (G62), even when unplugged, still shows temperatures of -49c. I also noticed that the gauge for oil pressure in the cockpit is showing 2 bar, whereas the actual pressure is 0.0 if i crank up the engine.
I don't know what to do. I feel like i've pretty much ruled everything else out. However, i'm afraid that I may have missed something. If anyone has any suggestions, please let me know! TIA!
3. Fuel Pump
The fuel pump in the g28 gets a signal from the RPM sensor. The GM-style sender is the same as the G4 and both function in the 80, 100 200, UrS and RS2 cars which is why you can easily locate one at a junkyard or at a parts store. Test them out by putting your DMM in resistance mode and take measurements between pins 1 (with the bump on the connector's side up) and 2 (2nd from left on the black end of the connector). They must be infinite ohms.
4. ECU
Our 20vt turbo (3B AAN, ABY, and ADU) engines have an ECU that has to know the position and speed of the crankshaft in order to make a decision about timing of the fuel injectors, etc. It utilizes a Crank Position Sensor G4 and an Engine Speed Sensor G28 to achieve this. If either of these go bad you will get codes on the diagnostic scanner that can lead to engine shutdown.
Some of the signs of a malfunctioning G28 sensor include an inaccurate gearbox rev counter and gears that shift faster than normal and/or a misfire when in gear. It is possible 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 when they're a Bosch unit like ours. Alternatively, the GM version of this part is also a great option.
5. Tachometer
A malfunctioning engine speed audi car key replacement sensor could be a cause for many issues with your car. It is an important part of the transmission of your Audi because it relays information to the ECU about how fast or slowly the engine is turning. If this sensor fails, it can cause problems for the transmission as click here well as the rest of the car's components.
The G5 engine speed sensor is located on the edge of the transmission, above the flywheel ring gear and transmits a signal to the ECU at pin T55/49, via a grey wire. The ECU then uses and processes the signal to control fuel, timig, and boost, and also sends it on to the G5 Tachometer located in the instrument cluster. You can test for sensor failure here by checking 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 [79]), and between pin T6a/1 as well as pin T26a/12. You should see an average resistance of 1000 ohms in these areas. This part here is common across the Audi 80-100-200-RS2 range, beginning with the 1985 MC and up to the 1997 UrS AN and 1995 RS2 DU You may also find them in wrecking yards.