Differential Pressure Regulator: Testing and Inspection

1. Build a test harness that connects between the EHA and its plug, that would allow testing both voltage and amperage. With the ignition on and the engine not running, the static current draw from the EHA should be 20mA. If the current differs significantly (but is greater than 0 mA), check to make sure that the terminals are free of corrosion and making good contact. If all else checks out good the control unit may be faulty.
a. If a 0 mA reading is shown, turn off the ignition and check the wiring for continuity between the EHA plug and the ECU.
b. If the wiring checks out, check the voltage supply to the ECU.
2. Test the resistance across the terminals of the EHA. It should read 19.5 ± 1.5 ohms. If the resistance is not within specifications, replace the EHA.
3. If everything else checks out within specification, replace the CIS-E control unit.