This Is The Ultimate Cheat Sheet For Audi G28
This Is The Ultimate Cheat Sheet For Audi G28
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How to Replace an Audi G28 Engine Speed Sensor
In this video Charles the Humble Mechanic shows how to replace the G28 engine speed sensor. This sensor is located on the outside of the transmission, above the flywheel gear. It transmits a signal to the ECU through a grey wire T55/49, then to the tachometer located on the instrument cluster.
1. Engine Speed Sensor
The grey wire is situated on the outside of the transmission, above the flywheel ring. This sensor sends a signal via the grey wire to pin T55/49. The ECU uses this information to control fuel and boost. It also sends a signal 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 be aware of when the crankshaft has reached TDC, and the location of the camshaft to trigger the spark and injectors.
If this sensor fails the ECU will throw a P00160 code which means the Crank Shaft and Intake Camshaft are out of sync and possibly indicating chain stretch or a jumped link on the upper chain of timing. The code won't appear without the additional information supplied by other sensors (G4 or G40).
Testing is a bit tricky because there are two connector pins, and they serve different purposes however the best method of testing it is by measuring resistance between the sensor and the ECU. If the sensor is functional, it should read around 1000 ohms. Examine for evidence of coolant or oil in the connector bay if you have issues with this component.
2. Injectors
Yesterday, while accelerating from the highway paytoll at full speed I noticed a massive drop in power. It was as if the engine had run out of gas. Or my injectors weren't firing. I took out the spark plugs this morning and found that 3 were soaked with gasoline and the 4th was dry. When I crank the engine without sparks, i place a tissue on the top of each of the injector holes and the 3 drenched with gazoline jump out but the 4th stays closed. I tested the ground connection on ECU pins 14/55, 30/55 and 48/55. i get 0ohm. Therefore, i think the issue is in another place.
I also tried to reset the PID 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 still occurs at higher RPM. The coolant temperature sensor (G62) shows the wrong temp value -49c even when i unplug it. Also i noticed that the gauge for oil pressure in the cockpit shows 2 bar while the actual pressure is 0.0 if i crank up the engine.
I'm not certain what to do, as i think i've pretty much completely ruled out all other read more possibilities. I'm worried that i might have missed something. Let me know if you have any ideas! TIA!
3. Fuel Pump
The fuel pump on the g28 is activated by a signal sent from the RPM read more sensor. The GM-style sensor 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 at a parts here store. It is simple to test them by putting your DMM in resistance mode and take measurements between pins 1 (with the bump on the connector end up) and 2 (2nd from the left on the black connector's end). They must be infinite Ohms.
4. ECU
Our 20vt turbo (3B, AAN, ABY and ADU) engines have an ECU that needs to know the speed and position of the crankshaft in order to make website decisions regarding fuel injector timing etc. In order to do this it makes use of a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If you encounter a problem with either of these sensors, the diagnostic scanner will display the codes that could trigger an engine shutdown.
The signs of a failed G28 website sensor are an inaccurate rev counter for the gearbox, gears shifting quicker than normal and/or misfiring when you are in gear. It is likely that the sensor is failing and requires to be replaced if you experience any of these symptoms. They're inexpensive and easy to locate especially if they're a Bosch sensor like ours. Alternatively, the GM version of this component is also a good option.
5. Tachometer
A failing engine speed sensor could be the reason behind many issues in your vehicle. It's a crucial component of the transmission of your Audi since it sends information to the ECU regarding how fast or slow the engine is turning. This sensor can cause the transmission to malfunction and other components of the car to be affected.
The G5 engine speed sensor is situated on the outside of the transmission, above the flywheel ring gear and transmits a signal to the ECU at pin T55/49 through a grey wire. The ECU utilizes this signal to control the amount of fuel and boost, as well as timig. It also sends it to the G5 Tachometer in instrument cluster. You can test for sensor failure by examining the continuity of the sensor to the tachometer. You can also check continuity between pin 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 a resistance of approximately 1000 ohms in these areas. This is a common feature across the Audi 80-100-200-RS2 model, ranging from the 1985 MC all the way up to the 1997 UrS AN and the 1995 RS2 DU So, you may find good ones in wrecking yards.