Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
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HOMESERVICE MANUALSCHEVROLET2008HHR LT, 2.4 P, AUTOMATICREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 106 (BATTERY, CHARGING SYSTEM AND STARTING SYSTEM)DIAGNOSTIC INFORMATION AND PROCEDURESDTC P0621CIRCUIT/SYSTEM TESTING2.0L LNF
2008 Chevrolet HHR LT, 2.4 P, Automatic
2.0L LNF
2008 Chevrolet HHR LT, 2.4 P, AutomaticSECTION 2.0L LNF
WARNING: This page is about a different car, the 2009 Chevrolet HHR. However, it is still accessible from the selected car via links, so may be relevant.
- Verify that a test lamp illuminates between the generator B+ terminal 1 X2 and ground. If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
- Ignition OFF, disconnect the X1 harness connector at the generator.
- Ignition ON, test for less than 1 V between the control circuit terminal B and ground. If greater than the specified range, test the control circuit for a short to voltage. If the circuit tests normal, replace the ECM.
- Engine running, command the L-Terminal ON to 85% with a scan tool. Test for greater than 3 V between the control circuit terminal B and ground. If less than the specified range, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the ECM.
- If all circuits test normal, test or replace the generator.
RENDER: 1.0x
NO RELATED
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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.