Emissions Inspection

Perform a visual and functional emissions inspection of the 1992 Dodge Viper's evaporative emission control system, catalytic converters, PCV system, and exhaust for leaks or component failure.

Warnings

Tools required

Preparation

1. Park vehicle on level surface and apply parking brake.
2. Place wheel chocks behind rear wheels.
3. Allow engine and exhaust system to cool completely if vehicle was recently driven.
4. Raise vehicle on lift or securely support on jack stands to access underside components.
5. Verify windshield and underhood emissions labels are present and legible (required for inspection in most jurisdictions).

Procedure

1. 1

   Retrieve diagnostic trouble codes
   Locate the diagnostic connector in the engine bay (verify exact location for this vehicle; typically near the battery/fender on Chrysler OBD-I products). Cycle the ignition key on-off-on-off-on within 5 seconds to enter self-diagnostic mode. Count the check engine light flashes to retrieve any stored trouble codes. Record all codes for reference. Code 12 (one flash, pause, two flashes) indicates the start of the diagnostic sequence. Code 55 indicates end of stored codes.
2. 2

   Inspect gas cap and fuel filler neck
   Remove the fuel filler cap and inspect the cap gasket for cracks, deterioration, or deformation. Check that the cap seal surface is clean and undamaged. Inspect the fuel filler neck for damage or corrosion. Verify the cap clicks at least 3 times when tightened to ensure proper seal. A faulty gas cap is the most common cause of evaporative emissions failures.
3. 3

   Inspect evaporative emission system components
   Visually inspect all evaporative emission system hoses and connections in the engine bay and under the vehicle. Check the charcoal canister (located near the fuel tank) for physical damage, saturation with liquid fuel, or disconnected hoses. Inspect vapor hoses from the fuel tank to the canister and from the canister to the throttle body for cracks, disconnections, or deterioration. Verify the purge solenoid on the intake manifold is properly connected.
4. 4

   Inspect PCV system
   Locate the PCV valve in the driver's side valve cover. Check that the PCV valve hose connection to the intake manifold is secure and the hose is not cracked or collapsed. Remove the PCV valve and shake it; a rattling sound indicates the valve is functional. Inspect the breather hose on the passenger side valve cover for proper connection and condition. Check for oil leaks around valve cover breather and PCV fittings.
5. 5

   Inspect exhaust manifolds and front exhaust pipes
   From underneath the vehicle, visually inspect both exhaust manifolds and the collector pipes for cracks, rust-through, or physical damage. Check all exhaust manifold-to-head connections and the collector pipe flange connections for evidence of exhaust leaks (black soot staining). Listen for any hissing sounds when engine is running that would indicate exhaust leaks upstream of the catalytic converters.
6. 6

   Inspect catalytic converters
   Locate any catalytic converter(s) present in the underbody exhaust system (verify the specific exhaust configuration for this vehicle, as early Vipers had a limited emissions/exhaust setup). Visually inspect both converter shells for physical damage, dents, road debris impact, or evidence of overheating (discoloration, melted heat shields). Check the inlet and outlet connections for leaks or loose hardware. Tap each converter lightly with a rubber mallet to check for internal substrate breakage (rattling indicates failure).
7. 7

   Inspect exhaust system from converters to tailpipes
   Continue visual inspection rearward from the catalytic converters to the mufflers and tailpipes. Check all pipe connections, flanges, and hangers for security and proper alignment. Look for holes, rust-through, or damage in any exhaust pipe section. Verify all rubber exhaust hangers are intact and supporting the system properly without excessive movement or contact with body/chassis components.
8. 8

   Inspect oxygen sensors
   Locate the oxygen sensor(s) in the exhaust system upstream of the catalytic converter(s) (verify sensor count and placement for this specific exhaust configuration). Visually inspect each O2 sensor wiring harness for damage, melting, or disconnection. Check that sensor connectors are fully seated and weather seals are intact. Look for exhaust leaks near the sensor bungs that would cause inaccurate readings.
9. 9

   Check for vacuum leaks
   With engine running at idle, listen for hissing sounds indicating vacuum leaks. Inspect all vacuum hoses connected to the intake manifold, brake booster, and fuel pressure regulator for cracks, disconnections, or deterioration. Pay particular attention to the large vacuum hose from the brake booster on the passenger side of the engine.
10. 10

    Verify EGR system (if equipped)
    The 1992 Viper V10 does not use an EGR valve system. Skip this step. Document this as 'N/A - no EGR on this platform' for inspection records.
11. 11

    Document findings and clear codes if applicable
    Record all inspection findings, noting any failed components, leaks, or damage requiring repair. If no issues were found and diagnostic codes were present only due to previous conditions (not current failure), clear codes by disconnecting the negative battery cable for 30 seconds, then reconnect. Re-run self-diagnostic to verify codes have cleared and no new codes are present.

Reassembly

1. No disassembly is required for this inspection procedure.
2. Lower vehicle from lift or jack stands.
3. Remove wheel chocks.

Verification

• Verify no diagnostic trouble codes are present after clearing and re-checking.
• Confirm check engine light (MIL) illuminates with key on, engine off, and extinguishes after engine start (normal operation).
• Start engine and verify no exhaust leaks are audible and exhaust flows smoothly from both tailpipes.
• Verify fuel cap is properly installed and clicks at least 3 times when tightened.
• Confirm all inspection findings have been documented for emissions certification or repair recommendations.

Related trouble codes on this vehicle

Codes that commonly send this job to the bay — tap one for symptoms, causes, and diagnostic steps.

Chasing one of these codes and not sure which part is guilty? Ask a master mechanic about YOUR car →

More procedures for this vehicle