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 shows 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 the grey wire (T55/49), then to the tachometer within the instrument cluster.
1. Engine Speed Sensor
Located on the edge of the transmission, above the flywheel ring gear the G28 Engine Speed Sensor sends an electrical signal to ECU pin T55/49 via an uncolored wire. The ECU utilizes this information to regulate fuel and boost. It also sends an indication to the G5 Tachometer located in the instrument cluster.
The sensor serves as a reference to correlate with the G40 Camshaft Position Sensor. The ecu needs to know when the crankshaft is TDC and where the camshaft is located so that it can start spark and injectors according to the situation.
If this sensor fails the ECU will throw a P00160 code which means the Crank Shaft and Intake Camshaft are out of sync and possibly indicating chain stretch or a jumped link on the upper timing chain. The code won't show without the additional information provided by other sensors (G4 or G40).
It is a little tricky to test since there are various pins on the connector, 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 be reading about 1000 ohms. Examine for evidence of coolant or oil in the connector bay if there are issues with this part.
2. Injectors
Yesterday, when accelerating from highway paytoll at a high speed I noticed a significant reduction in power. It was like the engine had run out of gas. Or, my injectors weren't firing. This morning i pull out the spark plugs, three were soaked with gazoline and the fourth was dry. I put a piece of tissue over each injector hole, and when i start the engine with no sparks, the 3 that have gazoline pop right out. The 4th one stays shut. I tried to test the ground connections of ECU pins 14,30, and 48/55. I found 0ohm. I'm assuming the issue is in another place.
I also tried to reset the PID with no success. The car will start when the G28 is unplugged, and it works fine when the G28 connected. However the intermittent misfire issue still occurs at higher RPM. The coolant sensor (G62) even when it is unplugged, shows a temperature of -49c. Also i noticed that the oil pressure gauge in the cockpit is showing 2 bar, whereas the actual pressure is 0.0 when I crank up the engine.
I'm not sure what to do, i think audi a4 key replacement i've pretty much eliminated everything else. But i'm worried that i might have missed something. If anyone has any audi replacement key uk ideas please chime in! TIA!
3. Fuel Pump
The fuel pump in the g28 is activated by a signal sent from the RPM sensor. The GM-style transmitter is identical to the G4 sender, and both operate on the 80,100,200, UrS, and RS2 vehicles. You can easily locate a spare in a wrecking shop or a parts store. It is easy to test them: simply switch your DMM into resistance mode get more info and test the distance between pins 1 and 2 (with the bump at the connector's end facing up). They should be infinite Ohms.
4. ECU
The ECU of our 20vt turbo (3B AAN ABY) engines requires to know the speed and position of the crankshaft to make decisions regarding fuel injector timing, etc. It uses a Crank Position Sensor G4 and an Engine Speed Sensor G28 to accomplish this. If you have a problem with either of these, the diagnostic scanner will show codes that could cause an engine shutdown.
A failing G28 sensor could result in an inaccurate speed counter for your gearbox or a gearbox that shifts more quickly than normal, and/or a misfire in gear. It is possible that the check here sensor is failing and needs to be replaced if you encounter any of these symptoms. They're cheap and easy to find, especially when they're an Bosch unit like ours. You can also choose the GM version of this part is also a great option.
5. Tachometer
A failing engine speed sensor could be the reason behind many issues in your vehicle. It's an essential component of the Audi's transmission as it sends information to the ECU about how the car's crankshaft is spinning. This sensor could cause the transmission to fail and other car components to be affected.
The G5 engine sensor is located near the edge of transmission, above the flywheel ring. It sends a signal via an uncolored wire to the ECU pin T55/49. The ECU is then able to process this signal to regulate fuel, timig, and boost and then transmitting it to the G5 tachometer inside the instrument cluster. You can test the sensor for failure by checking continuity between it and the tachometer, between the ECU pin T55/49 and the instrument cluster connection to pin T6a/1 (trace [79]) and between pin T6a/1 and the instrument cluster pin T26a/12. You should detect the resistance to be around 1000 ohms between these two points. This is a common feature across the Audi 80-100-200-RS2 series, starting from the 1985 MC up to the 1997 UrS AN and 1995 RS2 Du You may also find good ones in wrecking check here yards.