MBE 4000 DDEC VI Troubleshooting – Section 32.3 SPN 158/FMI 2

Section 32.3
SPN 158/FMI 2

This diagnostic is typically unmatched MCM and CPC signals.‪

Section 32.3.1
MCM and CPC Signals Check

Check MCM and CPC signals as follows:‪

1. Check for multiple codes.
   1. If fault codes 158/2 and 168/0 are both still active, refer to "32.1 SPN 168/FMI 0" .
   2. If fault codes 158/2 and 158/1 are both still active, refer to "32.2.1 Battery Voltage Switched – Low"
   3. If fault codes 158/2 and 158/0 are both still active, refer to "32.1.1 Battery High Voltage Check" .
   4. If fault codes 158/2 and 168/1 are both still active, refer to "32.2 SPN 168/FMI 1" .
   5. If only fault code 158/2 is active, go to step 2 .
2. Measure the difference in voltage inputs between the CPC and the MCM. See Figure "Power Wiring" .
   1. If the voltage difference is less than 1.0 V, contact the Detroit Diesel Customer Support Center (313–592–5800).
   2. If the voltage difference is greater than 1.0 V with the CPC indicating the low voltage, go to step 3 .
   3. If the voltage difference is greater than 1.0 V with the MCM indicating the low voltage, go to step 4 .
   

   Figure 1. Power Wiring

3. Replace or repair the bad contacts and/or voltage supply for pins 2/3 (ignition) and 2/2 (ground) of the CPC #2 connector. Refer to "32.3.1.1 Verify Repairs" .
4. Replace or repair the bad contacts and/or voltage supply for pin M21/7 (power) and pins M21/5, M21/6, M21/8, and M21/9 (ground) on the MCM 21-pin connector. Refer to "32.3.1.1 Verify Repairs" .

Section 32.3.1.1
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.