P0622 Generator Field F Control Circuit Malfunction 2

OBD-II Code P0622: This code indicates a malfunction in the generator field control circuit, which is responsible for regulating the voltage output of the alternator. The vehicle’s Powertrain Control Module (PCM) has detected an issue with this circuit.

p0622 – Generator Field F Control Circuit Malfunction

Typical Severity: Moderate

Common Causes

P0622 – Generator Field F Control Circuit Malfunction

Common causes:

• Faulty generator field control module
• Open or short circuit in the wiring for the generator field control circuit
• Loose or corroded electrical connections related to the generator field control circuit
• Defective generator (alternator)

Common Misdiagnosis

OBD2 Code: P0622

Description: Generator Field F Control Circuit Malfunction

Common Misdiagnosis: Replacing the alternator without checking for wiring issues or a faulty voltage regulator.

Common Diagnostic Steps

OBD2 Code: P0622

Description: Generator Field F Control Circuit Malfunction

• Check the battery voltage and ensure it is fully charged.
• Inspect the generator (alternator) wiring and connectors for damage or corrosion.
• Test the generator field control circuit for continuity and proper operation.
• Examine the drive belt for wear or slippage that could affect alternator performance.
• Use a multimeter to test the alternator output voltage and compare it with manufacturer specifications.
• Check for any blown fuses related to the charging system.
• If equipped, inspect the voltage regulator for faults or failure.
• Scan for additional trouble codes that may indicate other issues in the electrical system.