Your Worst Nightmare About Audi G28 Bring To Life
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. The sensor is located near the edges of the transmission just above the flywheel ring gear. It transmits a signal to the ECU through the grey wire T55/49 and then to the tachometer on the instrument cluster.
1. Engine Speed Sensor
The grey wire is situated at the edges of the transmission, above the flywheel ring. The sensor sends an electrical signal through the grey wire to pin T55/49. The ECU uses this information to regulate fuel and boost. It also sends an alert to the G5 Tachometer within the instrument cluster.
The sensor is used as a reference point to connect with the G40 Camshaft Position Sensor. The ecu needs to know 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 display a P00160 error message. This indicates that the Crank Shaft is not in alignment with the Intake Camshaft. It could also be a sign of the possibility of a chain stretch or jumpy chain link in the upper timing chain. However, the error code won't appear on its own without additional information from other sensors (G4 and G40).
Testing is a bit tricky since there are two pins for the connector and they have different functions but the most effective method to test it is by measuring resistance between the sensor and the ECU. audi key replacement should read around 1000 ohms if the sensor is operating at its maximum. Examine for signs of coolant or oil in the connector bay if you are experiencing issues with this component.
2. Injectors
Yesterday, while accelerating at full speed from the highway paytoll, I experienced massive power loss like the engine is out of gas or the injectors are not firing anymore. Today, i pulled out the spark plugs, three were drenched in gazoline, the fourth one was dry. When I start the engine without sparks, i place a tissue on top of each injector hole and the 3 drenched with gazoline pop out, but the 4th stays closed. I checked the ground connection on ECU pins 14/55/30/55/48/55/14/55/48/ I got 0ohm. I'm assuming that the issue is somewhere else.
I also tried to reset the PID with no success. The car will start when the G28 is unplugged, and it runs fine with the G28 connected. However the intermittent misfire issue persists at higher RPM. The temperature sensor for coolant (G62) shows the wrong temperature of -49c even when i unplug it. I also noticed that the oil gauge in the cockpit shows 2 bars when the actual pressure is 0.
I'm not sure what to do, as i feel i have pretty much completely ruled out all other possibilities. I'm worried that i might have missed something. If anyone has suggestions, please chime in! TIA!
3. Fuel Pump
The fuel pump in the g28 receives signals from 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. It is easy to find a spare in a wrecking shop or a parts store. It is simple to test them - just switch your DMM into resistance mode and measure the distance between pins 1 and 2 (with the bump at the connector end facing upwards). They should be infinite ohms.
4. ECU
The ECU in our 20vt turbo (3B AAN ABY ADU) engines needs to be aware of the position and speed the crankshaft to make decisions regarding timing of fuel injectors, etc. It makes use of a Crank Position Sensor G4 and an Engine Speed Sensor G28 to achieve this. If either of these goes wrong, you will receive codes on the diagnostic scanner that could cause engine shut down.
A damaged G28 sensor can cause an inaccurate speed counter for your gearbox, a gearbox that shifts more quickly than normal, and/or a misfire in gear. It is probable that the sensor is failing and needs to be replaced if you experience any of these signs. They're inexpensive and easy to locate particularly in the case of a Bosch model like ours. If you prefer, GM's version of this component is a good option.
5. Tachometer
A malfunctioning engine speed sensor could be the cause of many problems in your vehicle. It's a crucial component of the transmission in your Audi because it relays information to the ECU on how fast or slow the engine is turning. This sensor can cause the transmission to fail and other components of the car to be affected.
The G5 engine speed sensor is located on the outside of the transmission just above the flywheel ring gear. It sends a signal to the ECU at pin T55/49, via a grey wire. The ECU then uses and processes this signal to regulate fuel, timig, and boost, and also transmitting it to the G5 tachometer inside the instrument cluster. You can check for sensor failure by examining the continuity of the sensor to the tachometer. Also, you can verify continuity between pin T55/49 of the ECU and pin T6a/1 of the instrument cluster (trace [79trace [79]), and between pin T6a/1 as well as pin T26a/12. There should be the resistance to be around 1000 ohms between these two points. This is a common feature across the Audi 80-100-200-RS2 model, ranging from the 1985 MC up to the 1997 UrS An and 1995 RS2 DU You may also find some good ones in wrecking yards.
