MBE 900 DDEC VI Troubleshooting – Section 32.2 SPN 158/FMI 1

Section 32.2
SPN 158/FMI 1

The diagnostic condition is typically low system voltage.‪

Section 32.2.1
Battery Voltage Switched – Low

Check as follows:‪

1. Turn the ignition ON (key ON, engine OFF).
2. Measure the voltage across the battery terminals. See Figure "Power Wiring" .
   

   Figure 1. Power Wiring

   1. If the voltage is less than 11.0 V, troubleshoot the battery, starting, and charging system for an under voltage condition. Refer to the OEM Vehicle Manual.
   2. If the voltage is not less than 11.0 V, go to step 3 .
3. Measure the voltage between pins 2/2 and 2/3 of the CPC #2 connector (18-pin). See Figure "Power Wiring" .
   1. If the voltage is between 11.0 and 16 V, replace the CPC. Refer to "32.2.1.1 Verify Repairs" .
   2. If the voltage is 16 V, go to step 4 .
4. Start and run the engine. Measure the voltage drop between pin 2/3 of the CPC #2 connector and the positive battery terminal.
   1. If the voltage was less than 11.0 V (ignition on and engine not running) and voltage drop between pin 2/3 of the CPC #2 connector and the positive battery terminal is greater than 0.5 V (engine running), replace or repair the supply side wires and connectors between pin 2/3 of the CPC #2 connector and battery. Refer to "32.2.1.1 Verify Repairs" .
   2. If the voltage was not less than 11.0 V (ignition on and engine not running) and the voltage drop was not greater than 0.5 V, go to step 5 .
5. With the engine still running, measure the voltage drop between pin 2/3 of the CPC #2 connector and the negative battery terminal.
   1. If the voltage is less than 11.0 V and voltage drop between pin 2/3 of the CPC #2 connector and the negative battery terminal is greater than 0.5 V, replace or repair the ground side wires and connectors between pin 2/3 of the CPC #2 connector and battery ground. Refer to "32.2.1.1 Verify Repairs" .
   2. If the voltage is less than 11.0 V and voltage drop between pin 2/3 of the CPC #2 connector and the negative battery terminal is less than 0.5 V, contact the Detroit Diesel Customer Support Center (313–592–5800).

Section 32.2.1.1
Verify Repairs

Verify repairs as follows:‪

1. Turn ignition OFF.
2. Reconnect any electrical connections that were disconnected to perform the diagnosis.
3. Clear codes with DDDL 7.0 or latest version.
4. Start and bring engine up to operating temperature (over 140°F/60°C).
5. Verify operation is satisfactory and no warning lamps illuminate. If warning lamps illuminate, troubleshoot the codes. If assistance is required, call the Detroit Diesel Customer Support Center at 313–592–5800.