Test Description

2006 Isuzu Ascender S, 5.3 M, 4WDSECTION Test Description
WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 2004 Oldsmobile Bravada, 2004 GMC Envoy XUV, 2004 GMC Envoy XL, 2004 GMC Envoy, and 2004 Chevrolet TrailBlazer. However, it is still accessible from the selected car via links, so may be relevant.
DTC P0622

Step Action Value(s) Yes No
Schematic Reference: Starting and Charging Schematics 
Connector End View Reference:  Engine Electrical Connector End Views  
1 Did you perform the Engine Electrical Diagnostic System Check? - Go to Step 2  Go to Diagnostic System Check - Engine Electrical 
2
  1. Install a scan tool.
  2. Start the engine.
  3. With a scan tool, observe the GEN - F Terminal parameter in the PCM data list.
Does the scan tool indicate that the GEN - F Terminal parameter is within the specified range?
5-95% Go to Step 3  Go to Step 4 
3 With the scan tool command the generator OFF.
Does the GEN - F Terminal equal the specified value?
0% Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems Go to Step 4 
4
  1. Turn OFF the ignition.
  2. Disconnect the generator connector.
  3. Connect test lamp to battery positive voltage.
  4. Turn ON the ignition, with the engine OFF.
  5. Probe the F-Terminal in the generator connector.
  6. Observe the GEN - F Terminal Signal parameter in the PCM data list.
Is the GEN - F Terminal Signal parameter near the specified value?
100% Go to Charging System Test  Go to Step 5 
5 Test the generator field duty cycle signal circuit for a short or open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?
- Go to Step 8  Go to Step 6 
6 Inspect for poor connections at the harness connector of the PCM. Refer to Connector Repairs in Wiring Systems.
Did you find and correct the condition?
- Go to Step 8  Go to Step 7 
7 Replace the PCM. Refer to Powertrain Control Module (PCM) Replacement in Engine Controls - 4.2L.
Did you complete the repair?
- Go to Step 8  -
8
  1. Review and record the scan tool Fail Records data.
  2. Clear any DTCs.
  3. Operate the vehicle within the Fail Records conditions as noted.
  4. Using a scan tool, monitor the Specific DTC info for this DTC.
Does the scan tool indicate that this DTC failed this ignition?
- Go to Step 2  System OK
RENDER: 1.0x

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • You smell fuel, burning insulation, or see smoke.
  • Brakes feel soft, pull hard to one side, or make grinding noises.
  • The engine overheats, stalls repeatedly, or misfires under load.
  • You are missing required tools, torque specs, or safe lifting equipment.
  • You are not confident in the next step or safety outcome.