SYS.OK|MANUAL.DB● LIVE
HOMESERVICE MANUALSCHEVROLET2001CHEVY EXPRESS G2500, VAN CARGO EXTENDED, 5.7 R, L31/KL8REPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 9 (BODY CONTROL MODULES)DIAGNOSTIC TESTSDTC B1440: POWER MODE MASTER INPUT CIRCUIT MISMATCHTESTING
2001 Chevrolet Chevy Express G2500, Van Cargo Extended, 5.7 R, L31/KL8

DTC B1440: Power Mode Master Input Circuit Mismatch: Testing

2001 Chevrolet Chevy Express G2500, Van Cargo Extended, 5.7 R, L31/KL8SECTION Testing
WARNING: This page is about a different car, the 2002 Chevrolet Monte Carlo, 2002 Chevrolet Impala, 2001 Chevrolet Monte Carlo, and 2001 Chevrolet Impala. However, it is still accessible from the selected car via links, so may be relevant.
  1. Perform diagnostic system check for suspect system control module. See DIAGNOSTIC SYSTEM CHECK  table under SELF-DIAGNOSTIC SYSTEM. Repair as necessary and go to step  15. If diagnostic system check has been performed for suspect system control module, go to next step.
  2. Turn ignition switch to OFF position. Connect scan tool to Data Link Connector (DLC). Switch to BCM data display inputs on scan tool. Using scan tool, monitor IGNITION 0, IGNITION 1 and ACCESSORY SWITCH. All parameters should be off or inactive. If all parameters are not as specified, go to next step. If any parameter is not as specified, go to step  7.
  3. Turn ignition switch to ACCESSORY position. Ensure scan tool is in BCM data display inputs screen. Using scan tool, monitor IGNITION 0, IGNITION 1 and ACCESSORY SWITCH. IGNITION 0 and ACCESSORY SWITCH parameters should be active. If parameters are as specified, go to next step. If either parameter is not as specified, go to step  9.
  4. Turn ignition switch to RUN position. Ensure scan tool is in BCM data display inputs screen. Using scan tool, monitor IGNITION 0, IGNITION 1 and ACCESSORY SWITCH. All parameters should be on or active. If all parameters are as specified, go to next step. If any parameter is not as specified, go to step  9.
    5. NOTE: Turn ignition switch to OFF position immediately after reviewing input data.
  5. Turn ignition switch to START position. Ensure scan tool is in BCM data display inputs screen. Using scan tool, monitor IGNITION 0, IGNITION 1 and ACCESSORY SWITCH. IGNITION 0 and IGNITION 1 parameters should be active. If parameters are as specified, go to next step. If either parameter is not as specified, go to step  9.
  6. If any BCM data display inputs were not as specified in steps  2- 5 , go to next step. If all BCM data display inputs were as specified, in steps  2- 5 , go to step  12.
  7. Turn ignition switch to OFF position. Disconnect ignition switch connectors. Ensure scan tool is in BCM data display inputs screen. Using scan tool, monitor IGNITION 0, IGNITION 1 and ACCESSORY SWITCH. If IGNITION 0, IGNITION 1 or ACCESSORY SWITCH parameter is active, go to next step. If IGNITION 0, IGNITION 1 and ACCESSORY SWITCH parameters are not active, go to step  10.
  8. Disconnect BCM connectors. Check for short to power in suspect circuit (parameter indicated active). Repair as necessary and go to step  15. If short to power is not found, go to step  12.
  9. Turn ignition switch to OFF position. Disconnect ignition switch connectors. Connect a fused jumper wire (3-amp) between Black ignition switch harness connector terminal "A" (Red wire) and suspect circuit. Ensure scan tool is in BCM data display inputs screen. Using scan tool, monitor suspect circuit parameter (IGNITION 0, IGNITION 1 or ACCESSORY SWITCH). If suspect circuit is active, go to next step. If suspect circuit is still not active, go to step  11.
  10. Check for poor terminal contact at ignition switch harness connector. Repair as necessary and go to step  15. If ignition switch harness connector terminal contact is okay, go to step  13.
  11. Disconnect BCM connectors. Check for short to ground or open in suspect circuit (parameter indicated not active). Repair as necessary and go to step  15. If short to ground or open is not found, go to next step.
  12. Check for poor terminal contact at BCM harness connector. Repair as necessary and go to step  15. If BCM harness connector terminal contact is okay, go to step  14.
  13. Replace ignition switch and go to step  15. See IGNITION SWITCH  under REMOVAL & INSTALLATION.
  14. Replace and reprogram BCM. See BODY CONTROL MODULE  under REMOVAL & INSTALLATION. See BODY CONTROL MODULE  under PROGRAMMING. After repairs, go to next step.
  15. Turn ignition switch to OFF position. Reconnect any disconnected components and harness connectors. Using scan tool, clear DTCs. Operate vehicle within CODE ENABLE CRITERIA  conditions. Using scan tool, retrieve DTCs. If DTC B1440 resets, return to step  2. If DTC B1440 does not reset, system is okay.
RENDER: 1.0x

NO RELATED

Recommended Tools & Savings

Use the Manual With the Right Hardware

Pair factory procedures with proven DIY tools so the instructions are easier to execute.

Affiliate disclosure: We may earn a commission at no extra cost to you.

Shop Manual-Ready ToolsFree Quote CheckQuote Shield Pro

When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.