Diagnostic Procedures
WARNING: This page does not describe the selected car, but rather 10 other vehicles, including the 2002 Ford RV Cutaway, 2002 Ford Pickup, 2002 Ford F550 Super Duty, 2002 Ford F450 Super Duty, and 2002 Ford Excursion. However, it is still accessible from the selected car via links, so may be relevant.
Perform this test when directed by QUICK TEST. This test is only intended to diagnose the following components and circuits:
- Exhaust Backpressure Regulator (EPR)
- Wiring Harness Circuits (PWR GND & EPR Signal)
- Powertrain Control Module (PCM)
Valve position is controlled by switching output signal circuit to 12 volts inside PCM. ON/OFF time is dependent upon exhaust backpressure.
- Output Functions
EPR is a variable position valve that controls exhaust backpressure during cold ambient temperatures to increase cab heat and decrease amount of time needed to defrost windshield. PCM uses measured exhaust backpressure, intake air temperature and engine load to determine desired exhaust backpressure. - Detection & Management
An open or shorted to ground control circuit can be detected by an on-demand output circuit check performed during KOEO ON-DEMAND SELF-TEST. An exhaust backpressure step test, in which PCM commands and then measures specific preprogrammed pressures, is performed during KOEO ON-DEMAND SELF-TEST. If PCM detects an Exhaust Back Pressure (EBP) or Intake Air Temperature (IAT) sensor fault, it will disable exhaust backpressure regulator.