Test U: SCP Invalid Or Missing Data: Testing

WARNING: This page is about a different car, the 2002 Ford Pickup and 2002 Ford Cab & Chassis. However, it is still accessible from the selected car via links, so may be relevant.

NOTE: Always retrieve Powertrain Control Module (PCM) DTCs before Alternate Fuel Control Module (AFCM) DTCs. If any network "U" type DTCs are present, repair prior to PCM DTCs. If PCM DTCs are retrieved, go to DIAGNOSTIC TROUBLE CODE DEFINITIONS in SELF-DIAGNOSTICS - EEC-V - GASOLINE & NGV article and service DTCs as necessary.

CAUTION: Always disconnect bi-fuel relay module power supply 3-pin harness connector C495 before disconnecting or reconnecting compuvalve main harness connector C1294 to avoid damaging compuvalve or connectors. See Figure.

1) Check Communication With PCM
Turn ignition off. Connect scan tool to Data Link Connector (DLC). Turn ignition on. Using scan tool, access PCM and select an active PID. If communication is possible with PCM, turn ignition off and go to next step. If communication is not possible with PCM, go to TEST QA: UNABLE TO ACTIVATE SELF-TEST/SCP COMMUNICATION ERROR/DTC NOT LISTED under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V - GASOLINE & NGV article.

2) Check Communication With Compuvalve

Ensure scan tool is connected to DLC. Turn ignition on. Using scan tool, access AFCM and select an active PID. If communication is not possible with AFCM, go to next step. If communication is possible with AFCM, clear DTCs and retest. If DTC is set again, perform COMPUVALVE CHECK under QUICK TEST. If fault still exists, replace compuvalve.

3) Check Power To Compuvalve
Turn ignition off. Disconnect bi-fuel relay module power supply harness connector C495. Disconnect compuvalve harness connector C1294. Reconnect bi-fuel relay module power supply harness connector C495. Turn ignition switch to ON position. Using DVOM, measure voltage between chassis ground and compuvalve harness connector C1294 terminals No. 9 and 11 (White wires). See Figure. If all voltages are more than 10 volts, go to next step. If either voltage is 10 volts or less, repair open in affected circuit. See WIRING DIAGRAMS article.

4) Check Ground To Compuvalve

Turn ignition off. Ensure compuvalve harness connector C1294 is disconnected. Using DVOM, measure resistance between chassis ground and compuvalve harness connector C1294 terminals No. 57, 59, 61, 62, 63 and 64 (Black wires). See Figure. If all resistances are less than 5 ohms, go to next step. If any resistance is 5 ohms or more, repair open in affected circuit. See WIRING DIAGRAMS article.

5) Check SCP Link To DLC For Open Or Short To Ground

Ensure ignition is off. Ensure compuvalve harness connector C1294 is disconnected. Perform the following:
- Using DVOM, measure resistance between chassis ground and compuvalve harness connector C1294 terminals No. 14 and No. 16 (White wires). See Figure.
- Using DVOM, measure resistance of SCP (-) circuit between compuvalve harness connector C1294 terminal No. 16 (White wire) and DLC terminal No. 10 (Pink/Light Blue wire). Figure and Figure .
- Using DVOM, measure resistance of SCP (+) circuit between compuvalve harness connector C1294 terminal No. 14 (White wire) and DLC terminal No. 2 (Tan/Orange wire). See Figure and Figure .
If all resistances are more than 10 k/ohms between connector C1294 and chassis ground, and less than 5 ohms between connector C1294 and DLC, perform COMPUVALVE CHECK under QUICK TEST. If fault still exists, replace compuvalve. If any resistance measurement is 10 k/ohms or less between connector C1294 and chassis ground, or 5 ohms or more between connector C1294 and DLC, repair open or short to ground in affected SCP circuit. See WIRING DIAGRAMS article.