DTC P1618: SERIAL PERIPHERAL INTERFACE (SPI) PCM INTERPROCESSOR COMMUNICATION ERROR Honda Passport II

1. Perform On-Board Diagnostic (OBD) System Check. See BASIC DIAGNOSTIC PROCEDURES article. After performing OBD system check, go to next step.
2. If EEPROM calibration is latest version available, replace PCM. Retest system. If EEPROM calibration is not latest version, go to next step.
3. Reprogram PCM with latest available EEPROM calibration. Clear DTCs. If DTC P1618 resets, replace PCM. If DTC P1618 does not reset, repair is complete.

Diagnostic Aids

DTC P1625 stored by itself does not require diagnosis. Clear DTC.

1. Perform On-Board Diagnostic (OBD) System Check. See BASIC DIAGNOSTIC PROCEDURES article. After performing OBD system check, go to next step.
2. Turn ignition on. Install scan tool. Start and idle engine. Select DTC INFO on scan tool. If scan tool indicates DTC P1625 failed, go to next step. If scan tool indicates DTC P1625 failed, go to next step. If scan tool indicates DTC P1625 did not fail, see «DIAGNOSTIC AIDS»(ref-89316-S07387939392001022800000) .
3. Using scan tool, clear DTC P1625. Start and idle engine. Select DTC INFO. If scan tool indicates DTC P1625 failed, go to next step. If scan tool indicates DTC P1625 did not fail, see «DIAGNOSTIC AIDS»(ref-89316-S07387939392001022800000) .
4. Check vehicle for aftermarket electronic devices, such as phones, alarms, etc. If an aftermarket device is incorrectly installed PCM may detect a false sensor reading. Repair as necessary.

Check for poor connection, rubbed-through wire insulation or a broken wire inside insulation. Inspect harness connectors for backed-out terminals, improper mating, broken locks, improperly formed or damaged terminals, poor terminal-to-wire connection, and damaged harness. If DTC cannot be duplicated, check scan tool FAILURE RECORDS to determine mileage since last DTC was set.

1. Perform On-Board Diagnostic (OBD) System Check. See BASIC DIAGNOSTIC PROCEDURES article. After performing OBD system check, go to next step.
2. Check fuse for driver circuit that was shown as faulty. If fuse is blown, check for short circuit to ground between fuse and affected component. Replace fuse after repair. If fuse is not blown, go to next step.
3. Disconnect PCM connector for affected driver circuit. Repair damaged pins or terminals as necessary. If pins or terminals are okay, go to next step.
4. Check if either lamp circuit for CHECK ENGINE or CHECK TRANS is indicated as faulty by scan tool. If no fault is indicated, go to step 8 . If a fault is indicated, leave PCM connector for lamp driver circuit disconnect. Turn ignition on. Check voltage at PCM connector for affected lamp driver circuit. If battery voltage is present, replace PCM. If battery voltage is not present, go to next step.
5. Turn ignition on. Check for battery voltage at fuse for affected lamp driver circuit. If battery voltage is present, go to next step. If battery voltage is not present, repair open circuit between ignition switch and fuse.
6. Turn ignition off. Using DVOM, check for continuity between ground and affected driver terminal at PCM connector. If continuity exists, repair short to ground in affected driver circuit between affected component and PCM connector. Retest system. If continuity does not exist, go to next step.
7. Repair open in affected driver circuit between fuse and PCM connector. Retest system.
8. Reconnect PCM. Start engine and allow to idle. Using DVOM, backprobe affected terminal at PCM connector for battery voltage. If voltage is as specified, replace PCM. Retest system. If voltage is not as specified, go to next step.
9. Run engine at idle. Check for battery voltage to affected circuit fuse. If voltage is as specified, go to step 6 . If voltage is not as specified, repair open circuit between ignition switch and fuse. Retest system.

Check for poor connection, rubbed-through wire insulation or a broken wire inside insulation each component. Inspect harness connectors for backed-out terminals, improper mating, broken locks, improperly formed or damaged terminals, poor terminal-to-wire connection, and damaged harness. If DTC cannot be duplicated, check scan tool FAILURE RECORDS to determine mileage since last DTC was set.

1. Perform On-Board Diagnostic (OBD) System Check. See BASIC DIAGNOSTIC PROCEDURES article. After performing OBD system check, go to next step.
2. Check fuse for driver circuit that is shown as faulty. If fuse is not blown, go to next step. If fuse is blown, check for short circuit to ground between fuse and affected component. Replace fuse after repair.
3. Disconnect PCM connector for affected driver circuit. Check for damaged pins or terminals. Repair as necessary. If pins or terminals are okay, go to next step.
4. If either lamp circuits for CHECK ENGINE or CHECK TRANS are indicated as faulty by scan tool, go to next step. If either lamp circuit for CHECK ENGINE or CHECK TRANS are not indicated as faulty by scan tool, go to step 8 .
5. Leave PCM connector for lamp driver circuit disconnected. Turn ignition on. Measure voltage at PCM connector for affected lamp driver circuit. If battery voltage is present, replace PCM. If battery voltage is not present, go to next step.
6. Turn ignition on. Check for battery voltage at fuse for affected lamp circuit. If battery voltage is present, go to next step. If battery voltage is not present, repair open circuit between ignition switch and fuse.
7. Turn ignition off. Disconnect PCM connector for affected driver terminal. Connect ohmmeter between ground and PCM connector for affected driver. If continuity is present, repair short circuit to ground between affected component and PCM driver terminal. If continuity is not present, repair open circuit between fuse and PCM driver terminal.
8. Reconnect PCM. Start and idle engine. Backprobe affected terminal at PCM with voltmeter. If battery voltage is present, replace PCM. If battery voltage is not present, go to next step. If battery voltage is present, replace PCM.
9. Start and run engine at idle. Check for battery voltage at fuse for affected circuit. If battery voltage is present, go to step 7 . If battery voltage is not present, repair open circuit between ignition switch and fuse.