How to
replace audi key fob an
audi car keys G28 Engine Speed Sensor
In this video, Charles the Humble Mechanic demonstrates how to replace the G28 engine speed sensor. The sensor is located at the edge of transmission, above the flywheel gear. It sends a message to the ECU via an uncolored wire T55/49, then to the tachometer on the instrument cluster.
1. Engine Speed Sensor
Located on the edge of the transmission just above the flywheel ring gear, the G28 Engine Speed Sensor sends an electrical signal to ECU pin T55/49 through the grey wire. The ECU then utilizes this information to regulate fuel, timig and boost. It also sends an alert to the G5 Tachometer in instrument cluster.
The sensor is used to connect with the G40 Camshaft position Sensor. The ecu needs to know when the crankshaft has reached TDC and also the location of the camshaft in order to activate the spark and injectors.
If this sensor fails the ECU will show the P00160 error, which means the Crank Shaft and Intake Camshaft are out of sync, possibly indicating the chain is stretched or a jump link on the upper chain of timing. The code won't show without the additional information supplied by other sensors (G4 or G40).
Testing is a bit challenging since there are two connector pins and they serve different purposes but the most effective way to test it is to measure the resistance between the sensor and the ECU. It should read around 1000 ohms when the sensor is in full operation. Check for signs of coolant, or oil in the connector bay if there are problems with this part.
2. Injectors
Yesterday, when i was accelerating to the fullest speed from highway paytoll i had an abrupt drop in power like the engine is running out of gas or injectors are not firing anymore. Today, i pulled out the spark plugs, 3 were drenched with gazoline the fourth was dry. I placed a tissue over each injector hole and when i turn the engine on without sparks, the ones that have gazoline pop right out. The fourth one remains shut. I tested the ground connection of ECU pins 14,30 and 48/55. I found 0ohm. I assume that the problem is in another location.
I also tried to reset the PID but without success. The car can start when the G28 is disconnected and is running fine when it is connected, but still is experiencing intermittent misfires at higher RPM. The temperature sensor for coolant (G62) shows the wrong temp value -49c, even if I unplug it. I also noticed that the oil gauge in the cockpit shows 2 bars but 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 any ideas please share them! TIA!
3. Fuel Pump
The fuel pump of the g28 gets a signal from 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 the
spare audi key in a salvage shop or parts store. It is simple to test them - just switch your DMM into resistance mode and measure the distance between pins 1 and 2 (with the bump at the connector end facing up). They should be infinite ohms.
4. ECU
Our 20vt turbo (3B AAN, ABY, and ADU) engines are equipped with an ECU that needs to know the speed and position of the crankshaft to make decisions regarding timing of the fuel injectors, etc. In order to do this it makes use of a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If either of these sensors go badly, you will see codes on the diagnostic scanner that could cause engine shut down.
A malfunctioning G28 sensor could result in an inaccurate speed counter for your gearbox or a gearbox that shifts more quickly than normal, and/or a misfire in the gear. It is possible that your sensor is failing and requires to be replaced if you notice any of these symptoms. They're cheap and easy to find especially in the case of a Bosch sensor like ours. Alternately, GM's version this part is an excellent choice.
5. Tachometer
A failing engine sensor could cause a variety of issues in your vehicle. It's a crucial component of the transmission of your
audi key fob replacement cost, as it transmits information to the ECU regarding how fast or slowly the car's engine is turning. If the sensor fails, it will cause problems for the transmission as well as the rest of the car's components.
The G5 engine speed sensor is located at the outside of the transmission, above the flywheel ring gear and sends a signal directly to the ECU at pin T55/49, via a grey wire. The ECU is then able to process this signal to regulate the flow of fuel, timig and boost, and also sends it on to the G5 Tachometer located in the instrument cluster. You can determine if the sensor is in failure by examining the continuity from 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. It should show around 1000 ohms of resistance between these two points. This is a common feature across the
audi a1 car key 80-100-200-RS2 series, starting from the 1985 MC up to the 1997 UrS An and 1995 RS2 DU So, you may find good ones in wrecking yards.
