Test Description
The numbers below refer to the step numbers on the diagnostic table.
- 4 The exhaust system has very low back pressure under normal conditions. If the exhaust system is restricted, a significant increase in the exhaust pressure is noticed on the J-35314-A Exhaust Back Pressure Gauge. Removing the AIR check valve or HO2S sensor may set a DTC. When finishing this diagnostic table, be sure to clear all codes.
- 5 This step will isolate the catalytic converter from the remainder of the exhaust system.
- 8 Confirming that the condition has been fixed is essential. If the symptom still exists and the vehicle has a dual exhaust system, proceed to Step 2 and repeat diagnostic procedure on the opposite exhaust pipe.
| Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
| 1 | Did you verify the customers complaint? | Go to Step 2 | ||
| 2 | Did you review the exhaust symptoms diagnostic information and perform the necessary inspections? | Go to Step 3 | Go to Symptoms - Engine Exhaust | |
| 3 | Is the system equipped with dual exhaust? | Go to Diagnostic Aids | Go to Step 4 | |
| 4 | Remove the secondary air injection (AIR) check valve or the heated oxygen sensor (HO2S) that is in front of and closest to the catalytic converter. Refer to the affected component's service procedure. Install the J-35314-A Exhaust Back Pressure Gauge in place of the AIR check valve or HO2S sensor. Start the engine. Increase and monitor the engine speed at 2, 000 RPM. Observe the exhaust system back pressure reading on the gauge. Does the reading exceed the specified value? | 14 kPa (2 psi) | Go to Step 5 | Go to Step 8 |
| 5 | Turn the engine off and place the ignition in the lock position. Remove the J-35314-A Exhaust Back Pressure Gauge. Re-install the AIR check valve/HO2S sensor. Refer to the affected component's service procedure. Remove the post-catalyst HO2S sensor. Refer to the affected component's service procedure. Install the J-35314-A Exhaust Back Pressure Gauge in place of the post HO2S sensor. Start the engine. Increase and monitor the engine speed at 2, 000 RPM. Observe the exhaust system back pressure reading on the gauge. Does the reading exceed the specified value? | 14 kPa (2 psi) | Go to Step 6 | Go to Step 7 |
| 6 | Inspect the exhaust system for the following conditions: Damage in the exhaust pipe Debris in the exhaust pipe Muffler or resonator internal failure Two-layer exhaust pipe separation Did you find and correct the condition? | Go to Step 8 | ||
| 7 | Replace the catalytic converter. Refer to the affected component's service procedure. Did you find and correct the condition? | Go to Step 8 | ||
| 8 | Remove the J-35314-A Exhaust Back Pressure Gauge. Reinstall the AIR check valve or the post-catalyst HO2S sensor. Refer to the affected component's service procedure Clear any codes. Road test the vehicle in order to verify the repair. Did you correct the condition? | System OK | Go to Step 2 |
Restricted Exhaust
Exhaust System Description
| IMPORTANT | Use of non-OEM parts may cause driveability concerns. |
The exhaust system carries exhaust gases, treated by the catalytic converter, through the muffler and into a resonator, if applicable where exhaust noise is lessened.
In order to secure the exhaust muffler assembly to the exhaust manifold, a flange and seal-joint coupling is utilized. The exhaust system may utilize a slip-joint coupling design with a clamp and a U-bolt or a flange connection with a gasket.
Exhaust hangers and rubber insulators help to support the weight of the exhaust system along with insulating any exhaust system vibration, rattle or noise.
Exhaust hangers also space the exhaust system away from the underbody of the vehicle and allows the exhaust system to expand as the exhaust system warms up.
Exhaust heat shields are used to protect the underbody and other components from damage due to the heat from the exhaust system.
The exhaust system may be comprised of the following components
- Catalytic converter
- Exhaust hanger
- Exhaust heat shield
- Exhaust insulator
- Exhaust manifold
- Exhaust muffler
- Exhaust pipe
- Exhaust resonator, if equipped
- Exhaust tail pipe, if equipped