P26C8 on 2017-2019 Cadillac XT5 (Luxury, Premium Luxury, Platinum) — Chassis Control Module 1 Requested MIL Illumination
1 vehicles · 1 makes · $150-$800 repair
Most Reported On
P26C8 is an OBD-II diagnostic trouble code meaning “Chassis Control Module 1 Requested MIL Illumination.” An ISO/SAE-controlled powertrain code (not GM-proprietary, though it is most often reported on GM vehicles — Chevrolet, GMC, Buick, Cadillac). It does not describe a failure of its own: chassis control module 1 detected a fault it considers worthy of driver notification, sent a serial data message asking the engine control module to illuminate the MIL, and the ECM logged P26C8 to record that request. The real fault is stored as a separate DTC inside the chassis control module — the module that oversees chassis-side functions such as stability/traction control and electronically controlled suspension. Do not chase this code directly: scan all modules, find the DTC the chassis module actually set, and diagnose that. This code is most commonly reported on 2017-2019 Cadillac XT5 (Luxury, Premium Luxury, Platinum), with repair costs ranging from $150 to $800.
Common Causes
Typical Repair Cost
Based on 1 documented vehicle-specific issues. Actual cost depends on root cause and vehicle.
Diagnostic Tools
This is a powertrain code, so a basic OBD-II reader can read it. These read P26C8.
ANCEL AD310 Classic OBD-II Scanner
by ANCEL
A simple code reader for engine (P) codes on many compatible OBD-II vehicles. It does not support every vehicle or hybrid/EV application, and it does NOT read body, chassis or network codes; confirm exact-vehicle compatibility before buying.
- Read & clear engine (P) codes
- View freeze frame data
- I/M readiness status
- No batteries or app needed
BlueDriver Pro Bluetooth Scanner
by BlueDriver
Bluetooth scanner with a companion app that reads beyond the engine module — ABS, SRS and transmission — plus manufacturer-specific codes on many vehicles.
- Enhanced diagnostics (ABS, SRS, transmission)
- Repair Reports with verified fixes
- Smog check readiness
- Free app (iOS & Android)
LAUNCH CRP123X V3.0 Elite OBD-II Scanner
by LAUNCH
Handheld scanner covering the four major systems (engine, transmission, ABS, SRS) with live data streaming and graphing.
- Engine, transmission, ABS, SRS diagnostics
- Live data stream & graphing
- AutoVIN for vehicle identification
- Free lifetime updates via Wi-Fi
Autel MaxiCOM MK808S Diagnostic Tool
by Autel
Shop-level tablet with all-system coverage and bi-directional control, so you can command a module rather than only read it.
- All-system diagnostics (25+ modules)
- Bi-directional control & active tests
- Oil reset, EPB, BMS, TPMS, injector coding
- 7-inch touchscreen with Android OS
What you can do yourself, and what needs a shop
Reading the code, clearing it, and watching whether it returns is a driveway job with the right scanner. These steps are not:
- Module programming or software updates — needs the manufacturer software or a J2534 pass-through with a paid subscription.
- Replacing a control module — most are VIN-programmed and immobilizer-registered, so a new one does nothing until it is coded to your car.
- Airbag/SRS component work — a stored fault can deploy a live device.
If the vehicle is still under warranty, check for an open recall or technical service bulletin before buying anything — the repair may already be covered.
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FAQ
What does P26C8 mean?
P26C8 stands for "Chassis Control Module 1 Requested MIL Illumination." An ISO/SAE-controlled powertrain code (not GM-proprietary, though it is most often reported on GM vehicles — Chevrolet, GMC, Buick, Cadillac). It does not describe a failure of its own: chassis control module 1 detected a fault it considers worthy of driver notification, sent a serial data message asking the engine control module to illuminate the MIL, and the ECM logged P26C8 to record that request. The real fault is stored as a separate DTC inside the chassis control module — the module that oversees chassis-side functions such as stability/traction control and electronically controlled suspension. Do not chase this code directly: scan all modules, find the DTC the chassis module actually set, and diagnose that.
What are the most common causes of P26C8?
The most common causes of P26C8 are: An unrelated fault stored in the chassis control module (the actual root cause), Faults in chassis-side systems the module oversees — stability control, traction control, magnetic ride/electronic suspension, Outdated chassis control module software needing a reprogram, Serial data (CAN) bus wiring or connector faults between modules, Low system voltage or a weak battery triggering module faults, Failed chassis control module. The specific cause varies by vehicle.
How much does it cost to fix P26C8?
Repair costs for P26C8 range from $150 to $800, depending on the vehicle and root cause.
Which vehicles are affected by P26C8?
Au7o has documented P26C8 across 1 vehicle models from 1 manufacturers: Cadillac.
Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.