CAT ET 2019C Fault Codes — Two Code Systems
Caterpillar Electronic Technician 2019C reads fault codes in two formats depending on the engine age. Newer CAT engines (post-2008) use the SAE J1939 standard (SPN + FMI). Older CAT engines (pre-2008, including 3406E, C15 ACERT early series) use Caterpillar’s legacy MID/PID/FMI or CID/FMI format. CAT ET 2019C handles both transparently — no separate tool or adapter swap needed.
The fault codes below are sourced from NHTSA recalls and complaints for Caterpillar-powered trucks, plus common field faults documented across Kenworth T800 and Peterbilt 379 platforms.
Critical Fault Codes — NHTSA-Documented
VVA Oil Pressure Low — Variable Valve Actuation Fault
Source: NHTSA Recall 05V570000, Peterbilt 379 2006 with Caterpillar diesel engine
| Field | Value |
|---|---|
| System | Variable Valve Actuation (VVA) — Engine Lubrication |
| NHTSA Source | Recall 05V570000 — VVA oil line wears against cylinder head → oil leak + fire risk |
| CAT ET Display | VVA oil pressure parameter drop; event log entry for low VVA pressure |
Cause: VVA oil line positioned incorrectly, wearing against a sharp edge of the cylinder head. Over time the line is cut, causing an oil leak. No active J1939 fault code until pressure is lost — only visible in CAT ET event log and real-time VVA pressure parameter.
CAT ET Fix Steps:
- CAT ET → Parameters → Engine Lubrication → monitor VVA oil pressure in real-time
- Any pressure below specification during operation indicates a leak
- Inspect VVA oil line routing and reposition away from all cylinder head sharp edges
- Verify Recall 05V570000 remedy completion at nhtsa.gov using VIN
Oil Pressure Low — C11/C13/C15 (Oil Cap Event)
Source: NHTSA Recall 07V279000, Kenworth T800 2007 — CAT C11/C13/C15
| Field | Value |
|---|---|
| SPN | 100 (J1939) / PID 100 (legacy CID) |
| FMI | FMI 1 — Parameter below normal (low oil pressure) |
| NHTSA Source | Recall 07V279000 — oil fill cap dislodges, engine loses oil pressure, cap can lodge in steering driveline |
CAT ET Fix Steps:
- CAT ET → Event Log → look for SPN 100 FMI 1 events with timestamps
- Correlate event timestamps with any reported steering incidents
- Inspect oil fill cap and cap retention hardware on C11/C13/C15 engines
- Verify Recall 07V279000 completion on this VIN at nhtsa.gov
DPF Differential Pressure Fault
Source: NHTSA Recall 08V487000, Kenworth T800 2008 — DPF bracket separation
| Field | Value |
|---|---|
| SPN | 3251 (DPF differential pressure) |
| FMI | FMI 1 — Below normal (low differential pressure indicates DPF bypass) |
| NHTSA Source | Recall 08V487000 — DPF bracket insufficient stiffness → DPF separates from chassis |
CAT ET Fix Steps:
- CAT ET → Parameters → Aftertreatment → monitor DPF differential pressure
- A sudden drop to near-zero differential pressure indicates DPF bypass or physical separation
- Inspect DPF mounting brackets before assuming DPF is blocked — physical separation causes identical low-pressure reading as a missing filter
- Verify Recall 08V487000 on affected VINs
Common CAT Fault Code Reference
| SPN / CID | System | Description | Typical Fix |
|---|---|---|---|
| SPN 94 / PID 94 | Fuel | Fuel delivery pressure low (C15/C18) | Replace primary and secondary fuel filters; test transfer pump if filters don’t resolve |
| SPN 100 / PID 100 | Lubrication | Engine oil pressure low | Check oil level, pressure sensor, oil pump. See Recall 07V279000 for C11/C13/C15. |
| SPN 110 / PID 110 | Cooling | Engine coolant temperature high | Check coolant level, thermostat, water pump, radiator flow |
| SPN 174 / PID 174 | Fuel | Fuel temperature high | Check fuel cooler, fuel return line restriction, fuel tank temperature in hot climate operation |
| SPN 3251 | Aftertreatment | DPF differential pressure fault | Initiate forced DPF regen via CAT ET bi-directional tests. See Recall 08V487000. |
| SPN 3364 | Aftertreatment | DEF quality fault (C13/C15 with SCR) | Drain and replace DEF; inspect DEF quality sensor |
| SPN 91 | Engine | Throttle/accelerator position erratic | Inspect APS sensor and wiring; check for moisture at Deutsch connector |
| SPN 190 | Engine | Engine speed sensor fault | Check crankshaft position sensor air gap and wiring |
| CID 590 FMI 14 | ECM | ECM not responding (legacy format) | Check wiring to ECM power and ground; verify CA3/CA2 connection |
| CID 168 FMI 1 | Electrical | Battery voltage low (legacy format) | Test alternator output and battery capacity; inspect main power cables |
Legacy MID/PID/FMI Codes (Pre-2008 CAT Engines)
Older CAT engines (3406E, early C15 ACERT, C10, C12) use Caterpillar’s proprietary MID/PID/FMI format. CAT ET 2019C displays and decodes both formats automatically. Key identifiers:
- MID 36 — Engine ECM (all CAT on-highway engines)
- MID 74 — Transmission ECM (CAT automatic transmissions)
- MID 128 — Engine on newer J1939-based systems
CAT ET Software Error Messages
| Error | Cause | Fix |
|---|---|---|
| “No adapter detected” | CA3/CA2 drivers not installed or adapter not connected | Install CAT Communication Adapter drivers. Connect before launching CAT ET. |
| “ECM not communicating” | Ignition not on, wrong connector, or wiring fault to ECM | Turn key to ON. Check 9-pin connector seating and ECM power/ground. |
| “Flash file not available” | Internet not connected during ECM flash attempt | Verify internet connection. CAT ET connects to Cat factory server for each flash file. |
| “Factory password required” | Attempting to change protected programmable parameters | CAT factory password required. Contact CAT dealer service department. |
| “License validation failed” | Expired annual subscription or no internet | Renew CAT ET subscription or check internet connection. |
