How to Replace an Audi G28 Engine Speed Sensor
Charles the Humble Technician shows how to replace the G28 Engine Speed Sensor. This sensor is located on the outside of the transmission just above the flywheel gear. It sends a message to the ECU via the grey wire T55/49 and then to the tachometer in the instrument cluster.
1. Engine Speed Sensor
The grey wire is situated at the edges of the transmission, directly above the flywheel ring. This sensor sends signals through the grey wire to pin T55/49. The ECU utilizes this information to control fuel and boost. It also sends signals 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 has to know when the crankshaft reached TDC and also where the camshaft lies in order to activate the spark and injectors.
If this sensor fails the ECU will show a P00160 code which means the Crank Shaft and Intake Camshaft are out of sync and possibly indicating the chain is stretched or a jump link on the upper timing chain. However, the code won't appear on its own without additional information from other sensors (G4 and G40).
Testing is a bit challenging as there are two different connector pins, and they serve different purposes but the best way to test it is to measure resistance between the sensor and the ECU. When the sensor is functional, it should read around 1000 ohms. If you are having problems with this part, check for evidence of coolant or oil in the connector bay.
2. Injectors
Yesterday, as i was accelerating off the highway paytoll at maximum speed, i noticed a huge drop in power. It was as if the engine was running out of gas. Or my injectors were not firing. Today, i pulled out the spark plugs, 3 were drenched in gazoline, the fourth was dry. I placed a tissue over each injector hole, and when I turn the engine on without sparks, the 3 with gazoline jump right out. The 4th one remains closed. I checked the ground connection of ECU pins 14,30 and 48/55. I found 0ohm. Therefore, i think the issue is somewhere else.
I also tried to reset PID but without success. The car will start when the G28 is disconnected, but it works fine when the G28 plugged in. However, the intermittent misfire problem persists at higher RPM. The audi key replacement near me coolant sensor (G62) even when it is unplugged, shows an ice 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 if i crank up the engine.
I'm not sure what to do, as i think i've pretty much eliminated everything else. I'm worried that i might have missed something. If anyone has website any ideas please share them! TIA!
3. Fuel Pump
The fuel pump in the g28 receives signals from the RPM sensor. The GM-style transmitter is similar 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: simply switch your DMM into resistance mode and measure the distance between pins 1 and 2 (with the bump on the connector's edge facing up). They must be infinite Ohms.
4. ECU
The ECU of our 20vt turbo (3B AAN ABY) engines must be aware of the position and speed of the crankshaft to determine timing of fuel injectors, etc. In order to do this it uses 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 display the codes that could trigger the engine shutting down.
Some of the signs of a failing G28 sensor are an inaccurate rev counter in the replacement key for audi a4 gearbox and gears that shift faster than normal, and/or a misfire when you're in gear. If you have any of these problems, it is likely your sensor is failing and should be replaced. They're cheap and easy to find especially in the case of an Bosch sensor like ours. Alternatively, GM's version of this part is a good option.
5. Tachometer
A failing engine sensor could cause a variety of issues audi key replacement within your vehicle. It's an essential component of the Audi's transmission because it communicates to the ECU about how fast or slow the vehicle's crankshaft is turning. When this sensor fails, it could cause problems for the transmission as well as the rest of the car's components.
The G5 engine speed sensor is situated on the edge of the transmission, above the flywheel ring gear. It sends a signal directly audi a4 key replacement to the ECU at pin T55/49 through an uncolored wire. The ECU uses this signal to control the flow of fuel and boost as well as timig. It also sends it to the G5 Tachometer in instrument cluster. You can determine if the sensor is in failure by examining the continuity of the sensor to the tachometer. You can also examine the continuity between pins 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 an average resistance of 1000 ohms in these areas. This is a common feature across the Audi 80-100-200-RS2 range, from the 1985 MC up to the 1997 UrS An and 1995 RS2 DU, so you might find them in wrecking yards.