Common questions

What does the PCM power diode do?

What does the PCM power diode do?

The PCM power diode is put into the fuel pump and PCM relay power circuit to prevent power surge feedback into the circuit called flyback voltage then can be higher than normal operating voltage.

Where is the PCM on a 7.3 Powerstroke?

Open the hood and locate the computer (PCM) harness connector. It is located on the driver’s side firewall, beneath the brake master cylinder and next to the fender.

Does the IDM control fuel pump?

The IDM and not the PCM controls the firing of the injectors. The only thing the fuel pump feed does is either turn the pump on or not.

What is a diode in a fuse box?

Automotive Diodes & MINI Diodes Power diodes are designed to clamp surge voltages caused by electromagnetic components and perform uni-directional blocking of the flow of current in a circuit. These diodes are available in circuit board style or mini fuse style, which connects to mini fuse holders.

How do you test a PCM diode?

The Diode Test procedure is conducted as follows:

  1. Make certain a) all power to the circuit is OFF and b) no voltage exists at the diode. Voltage may be present in the circuit due to charged capacitors.
  2. Turn the dial (rotary switch) to Diode Test mode.
  3. Connect the test leads to the diode.
  4. Reverse the test leads.

What causes a 7.3 to lose power?

Overheating is a general issue the 7.3L Ford Power Stroke engine runs into. This could be related to the radiator, thermostat, water pump, cooling fan or bad coolant.

Does a used PCM need to be reprogrammed?

You will simply have to take your car to the dealership and set aside some time for them to make the updates. But if you purchased a used PCM as a replacement (usually from a vehicle that was totaled in an accident), you will need to have it reprogrammed for it to be able to work with your vehicle.

What is the difference between a PCM and IDM?

Make me smarter then the PCM is the brain and the IDM is the electric engine to fire the injectors.

What does a IDM do on a diesel?

The IDM (Injector Driver Module) is basically a dumb box that fires the injectors in response to a signal from the PCM telling it which injector to fire, when to fire it, and for how long.

What happens when a diode goes bad?

A bad (opened) diode does not allow current to flow in either direction. A multimeter will display OL in both directions when the diode is opened. A shorted diode has the same voltage drop reading (approximately 0.4 V) in both directions.

Is a diode the same as a fuse?

A fuse is a circuit protection device which is designed to blow when the amperage/current exceeds the specified rating of the fuse. A diode is a one way check valve of sorts. It allows current/voltage in one direction, but not the other.

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