How to Replace an
audi car key case G28 Engine Speed Sensor
In this video, Charles the humble mechanic demonstrates how to replace the G28 engine speed sensor. This sensor is situated near the transmission's edge, above the flywheel gear. It transmits a signal to the ECU through the grey wire T55/49 and then to the tachometer in the instrument cluster.
1. Engine Speed Sensor
The sensor is located at the edge of the transmission, above the flywheel ring gear the G28 Engine Speed Sensor sends an electrical signal to ECU pin T55/49 via an uncolored wire. The ECU utilizes this information to control boost and fuel. It also sends an alert to the G5 Tachometer located in the instrument cluster.
The sensor is used as a reference to correlate with the G40 Camshaft Position Sensor. The ecu has to know when the crankshaft reached TDC, and the location of the camshaft so that it can activate the spark and injectors.
If this sensor fails, the ECU will display an error code P00160. This means that the Crank Shaft is out of line with the Intake Camshaft. It could also be a sign of an issue with the chain or a jump in the chain link of the upper chain. The code won't show without the additional information supplied by other sensors (G4 or
Audi Car key Case G40).
It's a bit tricky to test as there are several pins on the connector and each one has different functions. The best way to do it is to measure the resistance between the ECU and the sensor. When the sensor is operational, it should be reading around 1000 ohms. If you are having problems with this component, look for evidence of oil or coolant in the connector bay.
2. Injectors
Yesterday, while accelerating at full speed from the highway paytoll, I experienced a big cut in power like the engine is out of gas or injectors aren't firing any more. Today, i pulled out the spark plugs, three were drenched in gazoline, the 4th one was dry. When I start the engine with no sparks, i place a tissue on the top of each hole in the injector and the 3 that were drenched in gazoline jump out but the 4th stay closed. I inspected the ground connection on ECU pins 14/55, 30/55 and 48/55. I get zero Ohm. I think the issue is elsewhere.
I also tried to reset the PID but with no luck. The car will start if the G28 is not plugged in and is running fine when it is plugged in, but still is experiencing intermittent misfires at higher RPM. The coolant sensor (G62) even when unplugged, still shows a temperature of -49c. Also i noticed that the gauge for oil pressure in the cockpit shows 2 bar, whereas the actual pressure is 0.0 if i crank up the engine.
I'm not sure what to do, i think i've pretty much completely ruled out all other possibilities. I'm concerned that i may have missed something. If anyone has suggestions, please let me know! TIA!
3. Fuel Pump
The fuel pump of the g28 receives a signal from the RPM sensor. The GM-style sender is the same as the G4 and they both work in the 80, 100 200, UrS and RS2 cars which is why you can easily locate one at a junkyard or from a parts store. It is easy to test them: simply switch your DMM into resistance mode and determine the distance between pins 1 and 2 (with the bump on the connector's edge facing upwards). They must be infinite ohms.
4. ECU
The ECU of our 20vt turbo (3B AAN ABY ADU) engines needs to be aware of the position and speed of the crankshaft in order to make a decision about timing of fuel injectors, etc. It makes use of a Crank Position Sensor G4 and an Engine Speed Sensor G28 to accomplish this. If you are experiencing issues with either of these sensors, the diagnostic scanner will show codes that could cause an engine shut down.
A failing G28 sensor could result in an inaccurate gearbox speed counter or a gearbox that shifts faster than normal, and/or an unfire when in the gear. If you are experiencing any of these problems, it is most likely that your sensor is going bad and needs replacing. The good news is they are quite affordable and readily available particularly when you're looking at the Bosch unit which is what ours are. Alternatively, GM's version of this component is a good option.
5. Tachometer
A faulty engine speed sensor could be the reason behind numerous issues with your vehicle. It is a crucial part of the Audi's transmission as it sends information to the ECU about how fast or slow the car's crankshaft is rotating. If this sensor fails, it can affect the performance of the transmission as well as the rest of the car's components.
The G5 engine sensor is located at the outskirts of the transmission, just above the flywheel ring. It sends a signal via gray wire to ECU pin T55/49. The ECU uses this signal to control the amount of fuel and boost, as well as timig. It also sends it to the G5 Tachometer located in the 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. You should see around 1000 ohms of resistance between these two points. This is a typical part across the
audi key fob not working 80, 100,
audi car Key Case 200, UrS and RS2 range from 1985 MC to the 1997 UrS AAN and 1995 RS2 ADU, so the best parts could be found in wrecking yards.