Operation CHARM: Car repair manuals for everyone.
Manuals through 2025 now available!

Our trusted friends have launched a new website named LEMON, which has newer manuals. It also contains all the CHARM manuals.

LEMON is the spiritual successor to CHARM, I recommend you try it!

Link: lemon-manuals.la or lemon-manuals.org.ua

(Some people have issue connecting. LEMON is investigating. For now, use Firefox or change your DNS server)

Or, hide this message: temporarily or permanently

Pinpoint Test 3: DTC P0620 - Generator Control Circuit



-
PINPOINT TEST 3: DTC P0620 - GENERATOR CONTROL CIRCUIT

Normal Operation

The PCM monitors the generator output via the generator monitor (GENMON) circuit. The PCM uses the generator communication (GENCOM) circuit to command the generator to either increase or decrease output. If the GENCOM circuit (generator control circuit) or the A sense circuit are open or shorted to ground, the PCM will be unable to control the generators output. When the engine rises above approximately 2,000 RPM, the generator will default to a steady voltage of approximately 13.5 volts and the PCM will send a request to the Instrument Cluster (IC) to illuminate the charging system warning indicator lamp.

- DTC P0620 Generator Control Circuit - If the GENCOM circuit or A sense circuit are open or shorted to ground, the PCM will set this DTC.

Possible Causes
- Fuse
- Wiring, terminals or connectors
- Generator
- PCM
- Radial arm adapter

Diagnostic Procedure

NOTE:Make sure battery voltage is greater than 12.2 volts prior to carrying out this pinpoint test.
NOTE:Do not have a battery charger attached during vehicle testing.

Step 1-Step 3:





Step 4-Step 6:





Step 7-Step 9:





Step 10-Step 12: