MBE 900 4000 Troubleshooting – Section 31.2 Troubleshooting SID 248

Section 31.2
Troubleshooting SID 248

The following procedure will troubleshoot SID 248.‪

Section 31.2.1
248 02 – Proprietary Datalink Fault

Perform the following steps to troubleshoot a proprietary datalink fault.‪

1. With the ignition switch set to the ON position and the engine not running, check for battery voltage at pin 15 on the small PLD-MR wiring harness connector on the 16-pin connector wiring harness. See Figure "PLD-MR Engine Bulkhead Schematic — Business Class" and see Figure "PLD-MR Engine Bulkhead Schematic — Acterra" for wiring schematics.
   1. If no battery voltage is measured, refer to "31.2.1.1 Required Actions" .
   2. If battery voltage is measured, go to step 2 .
2. Disconnect and reconnect the small harness connector (16-pin).
   1. If fault 248 02 is not active, refer to "31.2.1.2 Required Actions" .
   2. If fault 248 02 is active, go to step 3 .
3. Disconnect and reconnect the 15-pin connector.
   1. If fault code 248 02 is not active, refer to "31.2.1.3 Required Actions" .
   2. If fault code 248 02 is active, go to step 4 .
4. Check for continuity in wire 439D+ between 15-pin connector pin 13 and the small PLD-MR harness 16-pin connector pin 1. See Figure "PLD-MR Engine Bulkhead Schematic — Business Class" and see Figure "PLD-MR Engine Bulkhead Schematic — Acterra" for wiring schematics.
   1. If no continuity is measured, refer to "31.2.1.4 Required Actions" .
   2. If continuity is measured, go to step 5 .
5. Check for continuity in wire 439D- between 15-pin connector pin 15 and small PLD-MR harness 16-pin connector pin 2.
   1. If no continuity is measured, refer to "31.2.1.4 Required Actions" .
   2. If continuity is measured, refer to "31.2.1.5 Required Actions" .

Section 31.2.1.1
Required Actions

Perform the following steps to resolve a proprietary datalink fault.‪

1. Restore battery voltage at wire 15 on the small engine harness connector (16-pin) on the PLD-MR.

Section 31.2.1.2
Required Actions

Perform the following steps to resolve a proprietary datalink fault.‪

1. Clean or repair as required the terminals on the small engine harness connector (16-pin) plug on the PLD-MR. See Figure "PLD-MR Engine Bulkhead Schematic — Business Class" and see Figure "PLD-MR Engine Bulkhead Schematic — Acterra" for wiring schematics.
2. Erase the fault code memory.

Section 31.2.1.3
Required Actions

Perform the following steps to resolve a proprietary datalink fault.‪

1. Replace or clean the 15-pin connector contacts on the DDEC-VCU as required.
2. Erase fault code memory.

Section 31.2.1.4
Required Actions

Perform the following steps to resolve a proprietary datalink fault.‪

1. Replace the twisted wire pair set 439D- and 439D+ between the PLD-MR and the DDEC-VCU.
2. Erase the fault code memory.

Section 31.2.1.5
Required Actions

Perform the following steps to resolve a proprietary datalink fault.‪

1. Check the DDEC-VCU and PLD-MR ground wires for continuity.
2. Erase the fault code memory.

Section 31.2.2
248 14 – DDEC-VCU Internal Error

Perform the following step to troubleshoot a DDEC-VCU internal error fault.‪

1. Check for continuity in wires 439D- and 439D+ connecting the PLD-MR and the DDEC-VCU. See Figure "PLD-MR Engine Bulkhead Schematic — Business Class" and see Figure "PLD-MR Engine Bulkhead Schematic — Acterra" for wiring schematics.
   1. If continuity was not measured in wires 439D- and 439D+, refer to "31.2.2.1 Required Actions" .
   2. If continuity was measured in wires 439D- and 439D+, go to step 2 .
2. Check for a short to power between wires 439D- and 439D+ connecting the PLD-MR to the DDEC-VCU.
   1. If a short was measured, refer to "31.2.2.1 Required Actions" .
   2. If a short was not measured, go to step 3 .
3. Check for a short to ground in wires 439D- and 439D+ connecting the PLD-MR to the DDEC-VCU.
   1. If a short was detected, refer to "31.2.2.1 Required Actions" .
   2. If a short was not detected, refer to "31.2.2.2 Required Actions" .

Section 31.2.2.1
Required Actions

Perform the following steps to resolve a DDEC-VCU internal error fault.‪

1. Replace the twisted pair wire set 439D- and 439D+ between the PLD-MR and the DDEC-VCU.
2. Erase the fault code memory.

Section 31.2.2.2
Required Actions

Perform the following steps to resolve a DDEC-VCU internal error fault.‪

1. Inspect and clean the wire contacts as required.
2. Erase the fault code memory.