This Fault Code 527 document covers Fault Code 527 for Dual-Output Driver A on the ISB CM550 application group. It identifies PID P154, SPN 702, FMI 3, describes the OEM-controlled driver output, and gives diagnostic steps for OEM device and harness checks. The file is a 4-page English PDF intended for service troubleshooting, not a general engine manual.
Official Fault Code 527 document details
| Brand | Cummins |
|---|---|
| Model coverage | ISB CM550 (1990-94) |
| System/Group | DTCs; Dual-Output Driver A |
| Publication no. | Not stated in the extract |
| Year/Revision | Year unknown; source page shows Copywrite 2017 |
| Pages | 4 |
| File size | 0.4 MB |
| Format | |
| Language | English |
Document table of contents
- FAULT CODE: 527
- PID: P154
- SPN: 702
- FMI: 3
- DUAL-OUTPUT DRIVER A
- DESCRIPTION
- COMPONENT LOCATION
- TROUBLESHOOTING STEPS
- Step 1A) Turn key switch OFF and check for extra wires going to the OEM device.
- Step 1B) Turn key switch OFF and disconnect the control wire from the OEM device.
- Step 1C) Turn key switch OFF and disconnect the OEM harness.
- Step 2A) Turn key switch OFF and disconnect the OEM harness from the ECM.
- Step 2B) Turn key switch ON and disconnect the OEM harness from the ECM.
- Step 2C) Check for a short in the OEM device supply wire to ground.
- Step 2D) Check for a short circuit from pin to pin.
- Step 3A) Connect all components and disable the fault code.
- Step 3B) Clear the inactive fault codes using the diagnostic tool.
Applicable truck models
This document applies to Cummins ISB CM550 (1990-94) engines where Fault Code 527 is used for the Dual-Output Driver A circuit. The extract states that the OEM device is dependent upon the OEM, so the controlled device may be a fan clutch, air cleaner restriction indicator, or oil filter differential pressure indicator, depending on the vehicle installation. For official manufacturer information, visit Cummins.
Who needs this Fault Code 527 manual
Mechanics, electrical diagnostic technicians, and workshop owners need this manual when Fault Code 527 is active or inactive on an ISB CM550 and the repair path requires OEM device, ECM connector, and OEM harness testing. It supports checks for extra wires, dirty terminals, bent or corroded pins, open circuits, shorts to ground, pin-to-pin shorts, and final code clearing with a diagnostic tool.
The full PDF is available in the DiagTechPro manuals library, free account required to download.
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