Description
Used genuine PACCAR Q21-1055-1-100 Cab Electronic Control Unit (CECU) in serviceable condition, pulled from a 2008 Peterbilt. The CECU is the central body controller for late-2000s-era Kenworth and Peterbilt trucks — it bridges dash cluster, body lighting, HVAC controls, multiplexed switches, and the J1939 / J1587 data buses inside the cab.
Signs of a Failing CECU
- Multiple unrelated cab faults appearing simultaneously
- Intermittent or total loss of dash gauge or warning-lamp function
- HVAC, lighting, or accessory switches not responding
- J1939 / J1587>
- Diagnostic tool unable to communicate with the cab module
Specifications
| Manufacturer | PACCAR |
|---|---|
| Part Number | Q21-1055-1-100 |
| Part Type | CECU — Cab Electronic Control Unit |
| Pull Source | 2008 Peterbilt |
| Condition | Used — tested / good |
| Programming | Required (PACCAR ESA, by dealer) |
| Warranty | None |
| Core Charge | None |
Programming Required
This CECU is configured to a specific truck VIN at the factory and again whenever the module is replaced. Before installation it must be programmed to your truck’s build configuration using PACCAR ESA (Electronic Service Analyst) software at a Kenworth or Peterbilt dealer. An unprogrammed CECU will not communicate correctly with the rest of the cab’s electronics.
Applications
The Q21-1055-1-100 CECU was used on Kenworth and Peterbilt trucks in the 2007–2010 CECU platform window. Application varies by truck model, options, engine, and transmission — match the exact PACCAR part number on your existing module before ordering.
Confirm the part number printed on your existing CECU label exactly. PACCAR has used several similar Q21-prefix CECU part numbers across model years, and they are not interchangeable.
