Charging Circuit Troubleshooting

If the charging system indicator does not come on or does not go off, or the battery is dead or low, test the following items in the order listed below:
Battery
Charging system indicator
Alternator and regulator circuit
Alternator control system

Charging System Indicator Test


1.Turn the ignition switch ON (II).

Does the charging system indicator come on?


YES - Go to 2.


NO - Go to 3.


2.Start the engine.

Does the charging system indicator go off?


YES - Charging system indicator circuit is OK.n


NO - Go to 3.


3.Turn the ignition switch OFF.

4.Troubleshoot the multiplex control system.

Is the multiplex control system OK?


YES -

  • Without navigation system. Go to 7.
  • With navigation system. Go to 5.

NO - Check the multiplex control system as indicated by the Diagnostic Trouble Code (DTC).n


5.Disconnect the 12P connector from the AVN unit.

6.Start the engine.

Does the charging system indicator go off?


YES - Check that the terminals are firmly seated at the connectors. If OK, substitute a known-good AVN unit and recheck.n


NO - Go to 7.

7.Disconnect the engine wire harness 6P connector from the starter sub-harness 6P connector.

8.Measure the voltage at the No. 3 terminal of the engine wire harness 6P connector with the ignition switch ON (II).

 

Is there battery voltage?


YES - Go to 9.


NO - Check for a blown No.4 (10A) fuse in the under-dash fuse/relay box. If the fuse is OK, repair open in the wire between the alternator and the under-dash fuse/relay box.n


9.Turn the ignition switch OFF.

10.Disconnect the negative cable from the battery.

11.Disconnect Engine Control Module (ECM)/Powertrain Control Module (PCM) connector B (24P).

12.Check continuity between the ECM/PCM connector terminal B10 and engine wire harness 6P connector terminal No. 6.

 

Is there continuity?


YES - Go to 13.


NO - Repair open in the wire between the alternator and the  ECM/ PCM.n


13.Check continuity between the ECM/PCM connector terminal B10 and body ground.

 

Is there continuity?


YES - Repair short in the wire between the alternator and the  ECM/ PCM.n


NO - Reconnect the negative cable to the battery, and go to alternator and regulator test.

Alternator and Regulator Circuit Test


1.Be sure the battery is sufficiently charged and in good condition.

2.Raise the hoist to full height.

3.Hook up the ammeter, 0-400 A, to the starter sub-harness.

 

4.Lower the hoist.

5.Hook up the voltmeter, 0-20 V (accurate within 0.1 V), to T101.

 

6.Start the engine. Hold the engine at 3,000 rpm (min-1) with no load (in Park or Neutral) until the radiator fan comes on then let it idle.

7.Raise the engine speed to 2,000 rpm (min-1) and hold it there.

8.Turn the headlights (high beam) on, and measure voltage at the under-hood fuse/relay box terminal.

Is the voltage between 13.9 and 15.1 V?


YES - Go to 9.


NO - Repair or replace the alternator.n


9.Read the amperage at 13.5 V.

NOTE: Adjust the voltage by turning the blower motor, rear window defogger, brake lights, etc. ON.

Is the amperage 60A or more?


YES - Alternator/regulator operation is OK.n


NO - Repair or replace the alternator.n

Alternator Control System Test


1.Check for proper operation of the Electrical Load Detector (ELD) by checking the Malfunction Indicator Lamp (MIL).

2.Disconnect the engine wire harness 6P connector from the starter sub-harness 6P connector.

3.Start the engine, and turn the headlights (high beam) ON.

4.Measure voltage between the engine wire harness 6P connector terminal No. 2 and the positive terminal of the battery.

 

Is there 1 V or less?


YES - Go to 9.


NO - Go to 5.


5.Turn the headlights and ignition switch OFF.

6.Disconnect the negative cable from the battery.

7.Disconnect ECM/PCM connector B (24P).

8.Check for continuity between ECM/PCM connector terminal B18 and body ground.

 

Is there continuity?


YES - Repair short in the wire between the alternator and the ECM/PCM.n


NO - Check that the terminals are firmly seated at the connector. If OK, substitute a known-good ECM/PCM, and recheck.
If the prescribed voltage is now available, replace the original  ECM/ PCM.n


9.Turn the headlights and ignition switch OFF.

10.Disconnect the negative cable from the battery.

11.Disconnect ECM/PCM connector B (24P).

12.Check for continuity between ECM/PCM connector terminal B18 and engine wire harness 6P connector terminal No. 2.

 

Is there continuity?


YES - Repair or replace the alternator.n


NO - Repair open in the wire between the alternator and the  ECM/ PCM.n