How to Replace an Audi G28 Engine Speed Sensor
Charles the Humble Technician teaches you how to replace the G28 Engine Speed Sensor. The sensor is located near the transmission's edge just above the flywheel gear. It sends a message to the ECU via an uncolored wire T55/49, then to the tachometer located on the instrument cluster.
1. Engine Speed Sensor
The grey wire is located on the edge of transmission, directly above the flywheel ring. The sensor sends signals through the grey wire to pin T55/49. The ECU then utilizes this information to regulate fuel, timig and boost. It also sends a signal 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 must be aware when the crankshaft is TDC and the location of the camshaft so it can activate spark and injectors according to the situation.
If this sensor fails when it fails, the ECU will display an error code P00160. This means that the Crank Shaft is not in line with the Intake Camshaft. how much is a replacement audi key could also be a sign of an issue with the chain or a jumpy chain link in the upper chain. The code will not appear without the additional information supplied by other sensors (G4 or G40).
Testing can be a bit difficult because there are two pins for the connector and they have different functions but the best method of testing it is to measure the resistance between the sensor and the ECU. If the sensor is functional, it should read about 1000 ohms. Examine for evidence of coolant or oil in the connector bay if you have issues with this component.
2. Injectors
Yesterday, when accelerating from highway paytoll at a high speed I noticed a significant drop in power. It was like the engine was running out of gas. Or my injectors were not firing. I pulled out the spark plugs this morning, 3 were drenched in gasoline and the fourth was dry. When I start the engine with no sparks, I put a piece of tissue on top of each injector hole, the 3 drenched with gazoline jump out but the 4th stays shut. I checked the ground connection of ECU pins 14,30 and 48/55. I found 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 connected. However, the intermittent misfire problem still occurs at higher RPM. The coolant sensor (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 but the actual pressure is zero.
I'm not sure what to do, i feel i have pretty much ruled out everything else. I'm concerned that i may have missed something. Let me know should you have any suggestions! TIA!
3. how much is a replacement audi key in the g28 is activated by a signal from the RPM sensor. The GM-style sender is the same as the G4 and both are used in the 80 100, 200, UrS and RS2 cars which is why you can easily locate one at a wrecking yard or from a parts store. It is simple to test them: simply switch your DMM into resistance mode and test 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 in our 20vt turbo (3B AAN ABY ADU) engines requires to know both the position and speed the crankshaft to determine timing of the fuel injector, etc. To accomplish this, it utilizes a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If either of these go wrong, you will receive codes on the diagnostic scanner which can cause the engine to shut down.
A damaged G28 sensor can cause an inaccurate speed counter for your gearbox and a gearbox which shifts more quickly than normal, or a misfire while in gear. If you have any of these issues it is most likely that your sensor is failing and should be replaced. The good news is they are very cheap and easily accessible particularly when you're looking at a Bosch unit which is what ours are. If you prefer, GM's version of this part would be an option.
5. Tachometer
A faulty engine speed sensor could be the reason behind many issues with your car. It's a vital component of the Audi's transmission because it communicates to the ECU about how fast or slow the vehicle's crankshaft is turning. If the sensor fails, it could disrupt the performance of the transmission and the other car's components.
The G5 engine speed sensor is located at the edge of the transmission just above the flywheel ring gear and sends a signal to the ECU at pin T55/49 through an uncolored wire. The ECU utilizes this signal to control the amount of fuel and boost, and also timig. It also sends it to the G5 Tachometer inside the instrument cluster. You can check for sensor failure by examining the continuity from the sensor to the tachometer. Also, you can check 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. You should see approximately 1000 ohms resistance between those points. This part is common across the Audi 80-100-200-RS2 model, ranging beginning with the 1985 MC and up to the 1997 UrS AN and 1995 RS2 DU You may also find some good ones in wrecking yards.