This Is The Ultimate Cheat Sheet For Audi G28
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 situated on the outside of the transmission, above the flywheel gear. It transmits a signal to the ECU through a grey wire T55/49, then to the tachometer in the instrument cluster.
1. Engine Speed Sensor
The grey wire is situated on the outside of the transmission, just above the flywheel ring. The sensor transmits an electrical signal through the grey wire to pin T55/49. The ECU utilizes this information to control fuel and boost. It also sends an indication to the G5 tachometer inside the instrument cluster.
The sensor is used to correlate the G40 Camshaft position Sensor. The ecu must be aware of when the crankshaft has reached TDC, and the position of the camshaft, so that it can activate the spark and injectors.
If this sensor fails to function, the ECU will display an error code P00160. This means that the Crank Shaft is out of sync with the Intake Camshaft. It could also indicate an issue with the chain or a jump in the chain link of the upper timing chain. The code will not appear without the additional information provided by other sensors (G4 or G40).
It is a little tricky to test because there are several pins on the connector, and each one has different functions. The most effective method to test it is to measure the resistance between the ECU and the sensor. When the sensor is operational, it should be reading about 1000 ohms. Look for signs of coolant, or oil in the connector bay if you have problems with this part.
2. Injectors
Yesterday, when i was accelerating to the fullest speed from highway paytoll, i experienced massive power loss like the engine is running out of gas or the injectors are not firing at all. Today, i pulled out the spark plugs, three were soaked with gazoline and the fourth was dry. When I crank the engine with no sparks i put tissue on top of each injector hole and the 3 that were drenched in gazoline jump out but the 4th one stays closed. I checked the ground connection of ECU pins 14,30, and 48/55. I got zero ohm. I'm assuming the issue is elsewhere.
I also tried to reset the PID without success. The car will start when the G28 is unplugged, and it works fine when the G28 plugged in. However, the intermittent misfire problem persists at higher RPM. audi a3 key replacement (G62), even if it is not plugged in, shows an ice temperature of -49c. I also noticed that the oil gauge in the cockpit shows 2 bars while the actual pressure is 0.
I don't know what to do. I think I've eliminated everything else. I'm worried that i might have missed something. Please let me know If you have any suggestions! TIA!
3. Fuel Pump
The fuel pump in the g28 receives a signal from the RPM sensor. The GM-style transmitter 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 wrecking yard or at a parts store. Testing them is easy by putting your DMM in resistance mode and measure between pins 1 (with the bump on the connector's side up) and 2 (2nd from left on the black connector's end). They must be infinite Ohms.
4. ECU
The ECU of our 20vt turbo (3B AAN ABY) engines requires to be aware of the position and speed the crankshaft to determine timing of the fuel injector, etc. In order to do this it utilizes a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If you are experiencing issues with either of these sensors, the diagnostic scanner will show codes that could cause the engine shutting down.
A failing G28 sensor can cause an inaccurate speed counter for the gearbox and a gearbox which shifts more quickly than normal, and/or a misfire while in gear. If you have any of these issues it is likely that your sensor is deteriorating and should be replaced. They're inexpensive and easy to locate particularly when they're an Bosch sensor like ours. Alternatively, GM's version of this component is an excellent choice.
5. Tachometer
A malfunctioning engine speed sensor could be the cause of a slew of problems in your vehicle. It's a crucial component of the transmission of your Audi since it sends information to the ECU on how fast or slow the engine is spinning. If the sensor fails, it could disrupt the performance of the transmission as well as the other car's components.
The G5 engine speed sensor is situated on the outside of the transmission just above the flywheel ring gear and sends a signal directly to the ECU at pin T55/49 via a grey wire. The ECU then processes this signal to regulate the flow of fuel, timig and boost as well as transmitting it to the G5 tachometer inside the instrument cluster. You can check for sensor failure by checking continuity from the sensor to the tachometer. You can also 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. It should show around 1000 ohms of resistance between these two points. This is the same across the Audi 80-100-200-RS2 range, from the 1985 MC up to the 1997 UrS An and 1995 RS2 Du You may also find them in wrecking yards.