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 near the transmission's edge just above the flywheel gear. It sends a message to the ECU through a grey wire T55/49, then to the tachometer on the instrument cluster.
1. Engine Speed Sensor
It is located on the outside of the transmission, above the flywheel ring gear, the G28 Engine Speed Sensor sends an electrical signal to ECU pin T55/49 through an uncolored wire. The ECU then uses this information to control fuel, timig and boost. It also sends signals to the G5 tachometer inside the instrument cluster.
The sensor is used as a reference to correlate with the G40 Camshaft Position Sensor. The ecu must know when the crankshaft has reached TDC and also the location of the camshaft to trigger the spark and injectors.
If this sensor fails the ECU will show the P00160 error, which means the Crank Shaft and Intake Camshaft are not in sync and possibly indicating the chain is stretched or a jump link on the upper chain of timing. However the code will not be displayed on its own without additional information from other sensors (G4 and G40).
Testing is a bit challenging because there are two connector pins, and they perform different functions but the best method to test it is by measuring resistance between the sensor and the ECU. If the sensor is operational, it should be reading around 1000 ohms. Look for signs of coolant or oil in the connector bay if you are experiencing issues with this component.
2. Injectors
Yesterday, when i was accelerating to the fullest speed from highway paytoll, I experienced a big cut in power as if the engine was running out of gas or the injectors are not firing anymore. Today, i pulled 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 ones with gazoline jump right out. The 4th one stays closed. I checked the ground connection on ECU pins 14/55,30/55 and 48/55 i get 0ohm. I'm assuming that the issue is in another location.
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 value 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 certain what to do, but i feel i have pretty much ruled out everything else. I'm afraid i may have missed something. Please let me know should you have any suggestions! TIA!
3. Fuel Pump
The fuel pump in the g28 can be activated by a signal by the RPM sensor. The GM-style transmitter is similar to the G4 sender, and both operate on the 80,100,200, UrS, and RS2 vehicles. It is easy to find a spare in a wrecking shop or parts store. Testing them is easy to do - just put your DMM in resistance mode and measure between pins 1 (with the bump on the connector's end up) and 2 (2nd from left on the black connector's side). They should be infinite ohms.
4. ECU
The ECU of our 20vt turbo (3B AAN ABY) engines requires to know both the speed and position of the crankshaft to determine fuel injector timing, etc. To do this, it utilizes a Crank Position Sensor (G4) and an more info Engine Speed Sensor (G28). If either of these sensors go wrong, you will receive codes on the diagnostic scanner which can lead to engine shutdown.
A damaged G28 sensor could cause an inaccurate speed counter for your gearbox, a gearbox that shifts faster than normal, and/or a misfire while in gear. It is possible that your sensor is failing and needs to be replaced if you notice any of these here symptoms. They're inexpensive and easy to locate, especially if they're a Bosch unit like ours. Alternately, GM's version this component is an option.
5. Tachometer
A malfunctioning engine sensor can cause a number of problems in your vehicle. It's a crucial component of the transmission in your Audi, as it transmits information to the ECU regarding how fast or slow the engine of the car is spinning. This sensor can cause the transmission to fail and other components of the car to be affected.
The G5 engine sensor audi lost key replacement is located near the edge of the transmission, over the flywheel ring. It sends signals check here via a gray wire to the ECU pin T55/49. The ECU uses this signal to regulate the amount of fuel and boost, and also timig. It also transmits it to the G5 Tachometer located in the instrument cluster. You can test the sensor for any failure by checking the continuity between it and the tachometer, between ECU pin T55/49 and the instrument cluster connection via pin T6a/1 (trace [79]) as well as between T6a/1, and the instrument cluster pin T26a/12. There should be the resistance to be around read more 1000 ohms between these 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 So, you may find good ones in wrecking yards.