Charging Circuit Troubleshooting

Special Tools Required
Test pin box (  07XAZ-0010100)
 

Test harness (  070AZ-PWE0100)
 


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 / 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 9.


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.Disconnect the alternator 4P connector from the alternator.

5.Turn the ignition switch ON (II).

Does the charging system indicator come on?


YES -

  • Without navigation system: Turn the ignition switch OFF, and repair a short in the wire between the alternator and gauge assembly. If the wire is shorted to ground, the voltage regulator in the alternator may be damaged.n
  • With navigation system: Go to 6.

NO - Replace or repair the alternator.


6.Turn the ignition switch OFF.

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

8.Turn the ignition switch ON (II).

Does the charging system indicator come on?


YES - Turn the ignition switch OFF, and repair a short in the wire between the alternator and gauge assembly. If the wire is shorted to ground, the voltage regulator in the alternator may be damaged.n


NO - Check that the terminals are firmly seated at the connectors. If OK, substitute a known-good AVN unit and recheck.n


9.Connect the alternator 4P connector terminal No. 3 to body ground with a jumper wire. Turn the ignition switch ON (II).

 

Does the charging system indicator come on?


YES - Go to 10.


NO - Turn the ignition switch OFF. Check for a blown No. 16 (7.5A) fuse and a blown charging system indicator bulb. If the fuse and bulb are OK, repair an open in the wire between the gauge assembly and under-dash fuse/relay box.n

10.Measure the voltage between the alternator 4P connector terminal No.1 and body ground with the ignition switch ON (II).

 


Is there battery voltage?


YES - Go to Alternator and Regulator Circuit Test.n


NO - Repair an open in the wire between the alternator and the under-dash fuse/relay box.n

Alternator and Regulator Circuit Test


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

2.Hook up the following equipment:
  • Ammeter, 0-400A
  • Voltmeter, 0-20 V (accurate within 0.1 V)

 

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

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

5.Turn the headlights (high beam) on, and measure voltage at the alternator terminal.

Is the voltage between 13.9 and 15.1 V?


YES - Go to 6.


NO - Replace or repair the alternator.n


6.Read the voltage at 13.5V.

NOTE: Adjust the voltage by turn the blower motor, rear window defogger, brake lights and etc. on.

Is the voltage 60A or more?


YES - Alternator/regulator operation is OK. If the charging system indicator is still on, replace the alternator.n


NO - Replace or repair the alternator.n

Alternator Control System Test
(without ETCS)


1.Check for proper operation of the electrical load detecter (ELD) by checking that the malfunction indicator lamp (MIL) is off and there is no diagnostic trouble code (DTC) for ELD failure.

2.Disconnect the alternator 4P connector from the alternator.

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

4.Measure voltage between the alternator 4P connector terminal No. 2 and the positive terminal of the battery.


 

Is there 1 V or less?


YES - Go to 8.


NO - Go to 5.


5.Turn the headlight and ignition switch OFF.

6.Disconnect engine control module (ECM)/Powertrain Control Module (PCM) connector B (24P).

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


 

Is there continuity?


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

NO - Check that the terminals are firmly seated at the connectors. If OK, update the ECM/PCM if it does not have the latest software, or substitute a known-good ECM/PCM, then recheck. If the prescribed voltage is now available, and the ECM/PCM was substituted, replace the original ECM/PCM.n


8.Turn the headlight and ignition switch OFF.

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

10.Check for continuity between ECM/PCM connector terminal B18 and alternator 4P connector terminal No. 2.


 

Is there continuity?


YES - Replace or repair the alternator.n

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

Alternator Control System Test (with ETCS)


1.Check for proper operation of the ELD by checking that the MIL is off and there is no DTC for ELD failure.

2.Disconnect the alternator 4P connector from the alternator.

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

4.Measure voltage between the alternator 4P connector terminal No. 2 and the positive terminal of the battery.

 

Is there 1 V or less?


YES - Go to 8.


NO - Go to 5.


5.Turn the headlight and ignition switch OFF.

6.Connect the test harness and test pin box between the ECM and ECM connectors.

7.Check for continuity between pin box terminal No.34 and body ground.

Is there continuity?


YES - Repair a short to ground in the wire between the alternator and  ECM.n


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


8.Turn the headlight and ignition switch OFF.

9.Connect the test harness and test pin box between the ECM and ECM connectors.

10.Check for continuity between pin box terminal No.34 and alternator 4P connector terminal No. 2.

 

Is there continuity?


YES - Replace or repair the alternator.n


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