Where do you start looking for a 5V reference circuit?
Where do you start looking for a 5V reference circuit?
The easiest place to start testing is at one of the engine sensors (MAP, TPS, etc.). When you confirm that the 5V reference circuit is dead, you need to locate the source of the problem. The reference circuit may have as many as five to nine wires from the computer to different sensors on the vehicle. Where do you start looking?
What to do if your 5V reference circuit is dead?
When you confirm that the 5V reference circuit is dead, you need to locate the source of the problem. The reference circuit may have as many as five to nine wires from the computer to different sensors on the vehicle. Where do you start looking? As with any electrical problem, you need to review the vehicle’s wiring schematic.
What kind of problem is a 5V reference wire?
An example of this was a 2008 Subaru Outback that was towed in with a no-start condition. The vehicle cut out on the customer while he was driving. The wiring harness had rubbed on a support bracket under the intake manifold. The 5V reference wire was the first wire in the harness to be grounded.
What is the 5V reference circuit limiting resistor?
If the 5V reference circuit (in-series) limiting resistor, for example, is 50 ohms and the sensor is 25,000 ohms, then the amperage would be .000199A, or 199µA. The clamp-on amp meter will not be able to measure amperage that low.
What should the voltage be on my ECM PCM sensor?
If the meter reads 5.0 volts, the electrical circuit is good. If the meter reads other than 5 volts, ground one meter lead and test the 5 volt reference wire. It should read 5 volts. If it doesn’t you have a wiring or computer problem. Using the wiring diagram check the pin at the computer that supplies the 5 volts.
The easiest place to start testing is at one of the engine sensors (MAP, TPS, etc.). When you confirm that the 5V reference circuit is dead, you need to locate the source of the problem. The reference circuit may have as many as five to nine wires from the computer to different sensors on the vehicle. Where do you start looking?
When you confirm that the 5V reference circuit is dead, you need to locate the source of the problem. The reference circuit may have as many as five to nine wires from the computer to different sensors on the vehicle. Where do you start looking? As with any electrical problem, you need to review the vehicle’s wiring schematic.
An example of this was a 2008 Subaru Outback that was towed in with a no-start condition. The vehicle cut out on the customer while he was driving. The wiring harness had rubbed on a support bracket under the intake manifold. The 5V reference wire was the first wire in the harness to be grounded.
