Diagnostic Scan

Connect a diagnostic scan tool to the OBD-I connector to retrieve stored diagnostic trouble codes (DTCs) and system data from the 1992 Dodge Viper's Powertrain Control Module (PCM).

Warnings

Tools required

Preparation

1. Park vehicle on level ground and engage parking brake
2. Ensure ignition is in OFF position
3. Allow engine to cool if recently operated to avoid contact burns when reaching near exhaust components

Procedure

1. 1

   Locate the diagnostic connector
   The OBD-I diagnostic connector on the 1992 Viper is a Chrysler SCI-style connector, typically located in the engine compartment. Consult the factory service manual to confirm the exact connector location and pin configuration for this vehicle before proceeding.
2. 2

   Prepare the connector
   Remove any protective cover from the diagnostic connector. Inspect the connector pins for corrosion, damage, or debris. If corrosion is present, clean pins with electrical contact cleaner and allow to dry before proceeding.
3. 3

   Connect the scan tool
   With ignition OFF, connect the DRB-II or compatible OBD-I scan tool to the 6-pin diagnostic connector. Ensure the connector seats fully and locks into place if equipped with a retention mechanism. The tool should be securely connected before proceeding.
4. 4

   Power on the scan tool
   Turn the ignition key to the ON position (do not start engine). The scan tool should power up and establish communication with the PCM. Follow the tool's on-screen prompts to select 'Dodge', '1992', and 'Viper' from the vehicle selection menu. If using a DRB-II, navigate to the engine/powertrain module.
5. 5

   Retrieve diagnostic trouble codes
   Select 'Read Codes' or 'Fault Codes' from the scan tool menu. The tool will query the PCM and display any stored DTCs along with their descriptions. Record all codes and their frequency/status (current, pending, or history). Note that the 1992 Viper uses 2-digit Chrysler-specific fault codes, not the later standardized P-codes.
6. 6

   Review freeze frame data
   The 1992 OBD-I system does not provide OBD-II style freeze frame data. If your DRB-II supports a manual snapshot/record function, you may capture live sensor conditions during a fault event, but automatic per-code freeze frame data associated with stored codes is not available on this system.
7. 7

   Check live data stream
   Navigate to the 'Sensor Data' or 'Live Data' function. With engine off, review available parameters such as throttle position sensor voltage, coolant temperature sensor reading, and battery voltage. Verify readings are within expected ranges for key-on/engine-off conditions.
8. 8

   Perform running tests if needed
   If diagnosis requires live data with engine running, start the engine while scan tool is connected. Monitor real-time sensor data, fuel trim values, ignition timing, and other parameters as they update. Observe for erratic readings or values outside normal operating ranges. Allow engine to reach operating temperature if diagnostic procedures require it.
9. 9

   Perform actuation tests if applicable
   If the scan tool supports it and diagnosis requires component verification, use the actuation test function to command specific outputs (idle air control motor, fuel injectors, ignition coils). Listen and observe for proper component response. Return all components to normal operation before exiting this mode.
10. 10

    Clear codes if repairs completed
    If diagnostic codes were retrieved for documentation purposes or after completing repairs, use the 'Clear Codes' or 'Erase Codes' function to reset the PCM fault memory. Confirm that codes have been successfully cleared by re-reading the fault code list, which should now show no stored codes.
11. 11

    Disconnect scan tool
    Turn ignition to OFF position. Disconnect the scan tool from the diagnostic connector. Reinstall any protective cover on the connector. Store the scan tool and recorded diagnostic information.

Reassembly

1. Ensure diagnostic connector protective cover is reinstalled if equipped
2. Verify all engine compartment items are clear before starting vehicle
3. If codes were cleared, perform a drive cycle to allow the PCM to re-run diagnostic monitors and verify repairs

Verification

• Scan tool successfully communicated with PCM and retrieved data
• All diagnostic trouble codes were documented or successfully cleared
• Live data readings appeared reasonable for current engine operating conditions
• Diagnostic connector is properly covered and secured after procedure

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