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Test Description

WARNING: This page is about a different car, the 2017 Chevrolet Spark. However, it is still accessible from the selected car via links, so may be relevant.

The numbers below refer to the step numbers on the diagnostic table.

  1. 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 J-35314-A exhaust back pressure gauge.

    Removing the heated oxygen sensor may set a DTC. When finishing this diagnostic table all codes must be cleared.

  2. 4 

    This step will isolate the catalytic converter from the remainder of the exhaust system.

Restricted Exhaust

Step Action Value(s) Yes No
Special Tools 
J-35314-A  Exhaust Back Pressure Gauge
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 
  1. Remove the heated oxygen sensor 1. Refer to Heated Oxygen Sensor Replacement - Sensor 1 (L5Q)Heated Oxygen Sensor Replacement - Sensor 1 (LV7) .
  2. Install the EN-35314-A  exhaust back pressure gauge in place of the heated oxygen sensor 1.
  3. Start the engine.
  4. Increase and monitor the engine speed at 2, 000 RPM.
  5. Observe the exhaust system back pressure reading on the gauge.
  6. Check the value.
 - Go to Diagnostic Aids Go to Step 4 
4 
  1. Turn the engine off and place the ignition in the lock position.
  2. Remove the EN-35314-A  exhaust back pressure gauge.
  3. Install the heated oxygen sensor 1. Refer to Heated Oxygen Sensor Replacement - Sensor 1 (L5Q)Heated Oxygen Sensor Replacement - Sensor 1 (LV7) .
  4. Remove the heated oxygen sensor 2. Refer to Heated Oxygen Sensor Replacement - Sensor 2 (L5Q)Heated Oxygen Sensor Replacement - Sensor 2 (LV7) .
  5. Install the EN-35314-A  exhaust back pressure gauge in place of the heated oxygen sensor 2.
  6. Start the engine.
  7. Increase and monitor the engine speed at 2, 000 RPM.
  8. Observe the exhaust system back pressure reading on the gauge.
Compare the reading with the above value. The values are same?		 - 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 Catalytic Converter Replacement (LV7) Catalytic Converter Replacement (L5Q) .
Did you find and correct the condition?		 - Go to Step 7  -
7
  1. Remove the EN-35314-A  exhaust back pressure gauge.
  2. Install the heated oxygen sensor 2. Refer to Heated Oxygen Sensor Replacement - Sensor 2 (L5Q)Heated Oxygen Sensor Replacement - Sensor 2 (LV7) .
  3. Clear any DTCs.
  4. Road test the vehicle in order to verify the repair.
Did you correct the condition?		 - System Ok Go to Step 2 
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