The Most Worst Nightmare About Audi G28 Relived
How to Replace an audi a3 spare key G28 Engine Speed Sensor
In this video, Charles the humble mechanic demonstrates how to replace the G28 engine speed sensor. This sensor is located on the edge of the transmission, above the flywheel ring gear. It transmits a signal the ECU via the grey wire (T55/49) and then to the tachometer within the instrument cluster.
1. Engine Speed Sensor
The sensor is located at the edge of the transmission just above the flywheel ring gear, the G28 Engine Speed Sensor sends signals to ECU pin T55/49 through the grey wire. The ECU then uses this information to control the flow of fuel, timig and boost. It also sends signals to the G5 tachometer in the instrument cluster.
The sensor is used as a reference point to connect with the G40 Camshaft Position Sensor. The ecu must know when the crankshaft is TDC and where the camshaft is so it can trigger spark and injectors in the right way.
If this sensor fails, the ECU will throw a P00160 code which means the Crank Shaft and Intake Camshaft aren't in sync, possibly indicating the chain is stretched or a jump link on the upper chain of timing. However, the code won't appear on its own, without additional information from other sensors (G4 and G40).
It is a little tricky to test as there are several pins on the connector and they all have different functions. The best way to do it is by measuring the resistance between the ECU and the sensor. If the sensor is operational, it should be reading about 1000 ohms. Examine for evidence of coolant or oil in the connector bay if you have issues with this part.
2. Injectors
Yesterday, when i was accelerating to the fullest speed from highway paytoll, i experienced an abrupt drop in power like the engine is running out of gas or the injectors are not firing any more. 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 the top of each hole in the injector and the 3 that were drenched in gazoline jump out but the 4th one stays shut. I checked the ground connection on ECU pins 14/55,30/55 and 48/55 I got zero ohm. I'm assuming that the issue is elsewhere.
I also tried to reset PID but without success. The car will start when the G28 is disconnected and is running fine when it is plugged in but it still is experiencing intermittent misfires at higher RPM. The temperature sensor for coolant (G62) shows the wrong temperature value of -49c, even if I unplug it. I also noticed that the oil gauge in the cockpit shows 2 bars while the actual pressure is zero.
I'm not certain what to do, but 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 in the g28 receives 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 junkyard or from a parts store. It is simple to test them - put your DMM in resistance mode and measure the resistance between pins 1 (with the bump on the connector's end up) and 2 (2nd from left on the black end of the connector). They must be infinite Ohms.
4. ECU
Our 20vt turbo (3B AAN, ABY and ADU) engines have an ECU that must be aware of the speed and position of the crankshaft to make a decision about fuel injector timing etc. It makes use of a Crank Position Sensor G4 and an Engine Speed Sensor G28 to accomplish this. If you have a problem with either of these sensors, the diagnostic scanner will display codes that could cause an engine shutdown.
Some of the signs of a malfunctioning G28 sensor are an inaccurate rev counter in the gearbox and gears that shift faster than normal and/or a misfire when you are in gear. It is probable that the sensor is failing and needs to be replaced if you experience any of these signs. They're cheap and easy to find especially if they're a Bosch unit like ours. Alternately, GM's version this part is a good option.
5. Tachometer
A failing engine speed sensor could be the cause of numerous issues in your car. It's a crucial component of the transmission in your audi A3 Spare Key because it relays information to the ECU regarding how fast or slow the engine of the car is turning. This sensor could cause the transmission to fail and other car components to be affected.
The G5 engine sensor Replacement audi a3 key is located near the edge of the transmission, just above the flywheel ring. It sends a signal 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 to timigrate. It also sends it to the G5 Tachometer in instrument cluster. You can test the sensor key for audi failure by examining the continuity between it and the tachometer, between the ECU pin T55/49 and the instrument cluster connection on pin T6a/1 (trace [79]) and between pin T6a/1 and the instrument cluster pin T26a/12. You should detect a resistance of approximately 1000 ohms between these two points. This is the same across the replacement audi key 80-100-200-RS2 range, from the 1985 MC all the way up to the 1997 UrS An and 1995 RS2 DU, so you might find good ones in wrecking yards.