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Home >> Chevrolet >> 2005 >> Optra5 Base, Standard >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - 1.4L DOHC - DTC P0336 To DTC P1402 >> DTC P0501 >> Test Descriptions
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Test Descriptions

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

  1. 4:  Tests the signal circuit of the vehicle speed sensor (VSS) for an open or a short to ground.
  2. 5:  Tests the signal circuit of the vehicle speed sensor (VSS) for a short to voltage.
  3. 6:  Tests the ignition 1 voltage circuit of the vehicle speed sensor (VSS) for an open or a short to ground.
  4. 7:  Tests the ground circuit of the vehicle speed sensor (VSS) for an open or high resistance.
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. Clear the DTCs with a scan tool.
    3. NOTE: Support the lower control arms in the normal horizontal position in order to avoid damage to the drive axles. Do not operate the vehicle in gear with the wheels hanging down at full travel.
  3. Raise and support the drive wheels.
  4. Start and idle the engine.
  5. Engage the transmission into 2nd gear.
  6. Observe the Vehicle Speed Sensor parameter with a scan tool.
Is the vehicle speed more than the specified value?		 0 km/H. (0 mph) Go to Step 3  Go to Step 4 
3
  1. Observe the Freeze Frame/Failure Records data for this DTC.
  2. Turn OFF the ignition for 30 seconds.
  3. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records.
Did the DTC fail this ignition?		 - Go to Step 4  Go to Diagnostic Aids
4 
  1. Turn OFF the ignition.
  2. Disconnect the vehicle speed sensor (VSS) connector.
  3. Turn ON the ignition, with the engine OFF.
  4. Measure the voltage at the signal circuit of the VSS with a DMM.
Is the voltage within the specified range?		 9-11 V Go to Step 5  Go to Step 8 
5  Probe the signal circuit of the VSS with a test lamp connected to a good ground.
Does the test lamp illuminate?		 - Go to Step 8  Go to Step 6 
6  Measure the voltage at the ignition 1 voltage circuit of the VSS with a DMM.
Is the voltage within the specified range?		 11-14 V Go to Step 7  Go to Step 12 
7  Measure the resistance between the ground circuit of the VSS and battery ground with a DMM.
Is the resistance less than the specified value?		 5 Ω Go to Step 9  Go to Step 13 
8 Test the VSS signal circuit for one of the following conditions:
  • An open
  • A short to ground
  • A short to voltage
  • A high resistance

Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 16  Go to Step 11 
9
  1. Remove the VSS.
  2. Inspect the VSS and the transmission for the following conditions:
    • Incorrect VSS
    • VSS damage
    • Excessive VSS to speed sensor rotor gap
    • Incorrect VSS rotor alignment
    • VSS rotor damage
  3. Repair any of the above conditions as necessary.
Did you find and correct the condition?		 - Go to Step 16  Go to Step 10 
10 Test for shorted terminals and poor connections at the VSS. 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 16  Go to Step 14 
11 Test for shorted terminals and poor connections at the 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 16  Go to Step 15 
12 Repair the ignition 1 voltage circuit between the VSS connector and the fuse for an open or a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you complete the repair?		 - Go to Step 16  -
13 Repair the VSS ground circuit for an open or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you complete the repair?		 - Go to Step 16  -
14 Replace the VSS.
Did you complete the replacement?		 - Go to Step 16  -
15 Replace the ECM. Refer to Engine Control Module (ECM) Replacement .
Did you complete the replacement?		 - Go to Step 16  -
16
  1. Clear the DTCs with a scan tool.
  2. Turn OFF the ignition for 30 seconds.
  3. Start the engine.
  4. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records.
Did the DTC fail this ignition?		 - Go to Step 2  Go to Step 17 
17 Observe the Capture Info with a scan tool.
Are there any DTCs that have not been diagnosed?		 - Go to Diagnostic Trouble Code (DTC) List System OK
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