MBE 900 DDEC VI Troubleshooting – Section 42.3 SPN 558/FMI 4

Section 42.3
SPN 558/FMI 4

This diagnostic condition is typically a short to ground.‪

Section 42.3.1
Short to Ground Check

Check as follows:‪

1. Disconnect the Idle Validation Switch. See Figure "Idle Validation Switch, Part of the Accelerator Pedal Assembly" .
   

   Figure 1. Idle Validation Switch, Part of the Accelerator Pedal Assembly

2. Disconnect the CPC #1 connector.
3. Measure the resistance between pin 4 of the Idle Validation Switch connector and ground.
   1. If the resistance is less than 5 Ω, repair the short to ground between pin 6 of the CPC #1 connector and pin 4 of the Idle Validation Switch connector. Refer to "42.3.1.1 Verify Repairs" .
   2. If the resistance is greater than 5 Ω, go to step 4 .
4. Measure the resistance between pin 5 of the Idle Validation Switch connector and ground.
   1. If the resistance is less than 5 Ω, repair the short to ground between pin 3 of the CPC #1 connector and pin 5 of the Idle Validation Switch connector. Refer to "42.3.1.1 Verify Repairs" .
   2. If the resistance is greater than 5 Ω, replace the Idle Validation Switch.

Section 42.3.1.1
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.