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Home › Chevrolet › 2004 › Optra Base, Automatic › Repair and Diagnosis › Engine Performance › System › Engine Controls - 1.4L DOHC - DTC P1402 To DTC P1661 › DTC P1513 › Test Description

Test Description

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

  1. 5:  This step tests for a high resistance on the ISC motor position sensor 5-volt reference circuit.
Step Action Values Yes No
Schematic Reference:  Engine Controls Schematics 
Connect End View Reference:  Engine Controls Connector End Views 
1 Did you perform the Diagnostic System Check - Engine Controls? - Go to Step 2  Go to Diagnostic System Check - Engine Controls
2
  1. Turn ON the ignition, with the engine OFF.
  2. Observe the DTC information with a scan tool.
Is DTC P0106, P0122, P0123, P0222, P0223, P0462, P0463, P0510, P1511, or P1512 also set?		 - Go to Diagnostic Trouble Code (DTC) List Go to Step 3 
3
  1. Start the engine.
  2. Observe the ISC motor position sensor parameter with a scan tool while depressing the accelerator pedal.
Does the ISC motor position sensor parameter change when the throttle is open?		 - Go to Step 4  Go to Step 5 
4
  1. Turn OFF the ignition for 30 seconds.
  2. Start the engine.
  3. Operate the vehicle within the Conditions for running the DTC.
Does the DTC fail this ignition cycle?		 - Go to Step 5  Go to Intermittent Conditions
5 
  1. Turn OFF the ignition.
  2. Disconnect the throttle body harness connector.
  3. Turn ON the ignition, with the engine OFF.
    4. NOTE: Do NOT use the low reference circuit in the component harness connector for this test. Damage to the control module may occur due to excessive current draw.
    IMPORTANT: Use a test lamp that measures more than 20 ohms for this test.
  4. Connect a test lamp between the 5-volt reference circuit of the ISC motor position sensor and a good ground.
  5. Connect a DMM to the probe of the test lamp and a good ground. Refer to Measuring Voltage Drop in Wiring Systems.
Is the voltage more than the specified value?		 4.8 V Go to Step 7  Go to Step 6 
6 Test the 5-volt reference circuit of the ISC motor position sensor for a high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
 
Did you find and correct the condition?		 - Go to Step 11  Go to Step 8 
7 Test for an intermittent and for a poor connection at the throttle body assembly. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 11  Go to Step 9 
8 Test for an intermittent and for a poor connection at the engine control module (ECM). Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 11  Go to Step 10 
9 Replace the throttle body assembly. Refer to Throttle Body Assembly Replacement .
Did you complete the replacement?		 - Go to Step 11  -
10 Replace the ECM. Refer to Engine Control Module Replacement .
Did you complete the replacement?		 - Go to Step 11  -
11
  1. Clear the DTCs with a scan tool.
  2. Turn the ignition OFF for 30 seconds.
  3. Start the engine.
  4. Operate the vehicle within the Conditions for Running the DTC.
Does the DTC fail this ignition?		 - Go to Step 2  Go to Step 12 
12 Are there any DTCs that have not been diagnosed? - Go to Diagnostic Trouble Code (DTC) List System OK
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