Test Description
The numbers below refer to the step numbers on the diagnostic table.
- 3 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 EN-35314-A gauge. Removing the heated oxygen sensor may set a DTC. When finishing this diagnostic table, be sure to clear all codes.
- 4 This step will isolate the catalytic converter from the remainder of the exhaust system.
- 7 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 | Remove the heated oxygen sensor 1. Refer to Heated Oxygen Sensor Replacement - Sensor 1 , for the 1.4L or Heated Oxygen Sensor Replacement - Sensor 1 for the 1.6L. Install the EN-35314-A gauge in place of the heated oxygen sensor 1. 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 4 | Go to Step 7 |
| 4 | Turn the engine off and place the ignition in the lock position. Remove the EN-35314-A gauge. Install the heated oxygen sensor 1. Refer to Heated Oxygen Sensor Replacement - Sensor 1 , for the 1.4L or Heated Oxygen Sensor Replacement - Sensor 1 for the 1.6L. Remove the heated oxygen sensor 2. Refer to Heated Oxygen Sensor Replacement - Sensor 2 , for the 1.4L or Heated Oxygen Sensor Replacement - Sensor 2 for the 1.6L. Install the EN-35314-A gauge in place of the heated oxygen sensor 2. 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? | Go to Step 5 | Go to Step 6 | |
| 5 | 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 7 | ||
| 6 | Replace the catalytic converter. Refer to Warm Up Three-Way Catalytic Converter Replacement (LUV,LUW) . Did you find and correct the condition? | Go to Step 7 | ||
| 7 | Remove the EN-35314-A gauge. Install the heated oxygen sensor 2. Refer to Heated Oxygen Sensor Replacement - Sensor 2 , for the 1.4L or Heated Oxygen Sensor Replacement - Sensor 2 for the 1.6L. Clear any DTCs. 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
Note. Use of Non-OEM parts may cause driveability concerns.
The exhaust system carries exhaust gases, treated by the catalytic converter, through a resonator, if applicable and into the exhaust muffler where exhaust noise is lessened.
In order to secure the exhaust pipe to the exhaust manifold, a flange and seal-joint coupling is utilized.
Exhaust hangers and rubber insulators help to support the weight of the exhaust pipe 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 body and other components from damage due to the heat from the exhaust system.
The exhaust system may be comprised of the following components
- Exhaust manifold
- Exhaust pipes
- Catalytic converters
- Exhaust muffler
- Exhaust resonator, if equipped
- Exhaust hangers
- Exhaust heat shields