obdash/handoff.md

Handoff — ford-obd / 6.0 Power Stroke no-start

Pick-up notes for diagnosing the truck in the cab. Repo: git.jpaul.io/justin/ford-obd (private).

TL;DR — what to do at the truck

1. CH340 ELM327 adapter → OBD port (under dash, driver side).
2. Key to RUN (not ACC). Engine off is fine for reading codes.
3. On the Windows laptop, in the repo folder: double-click RUN_OBD.bat (or python obd_reader.py). If no port found: python obd_reader.py COM5.
4. Read the codes + the no-start triage it prints. Write the codes down.
5. To erase codes after reading: python obd_reader.py COM5 --clear (it asks you to type CLEAR).

Hardware confirmed

• Adapter chip: QinHeng CH340 (USB 1a86:7523), ELM327 v1.5 clone.
• Working baud: 38400 (default in the tool). If you get garbage, try 9600.
• It's an AT@2 = ? clone (no stored serial) — normal, works fine for generic OBD-II.

What the tool does / doesn't

• DOES: read stored/pending/permanent codes, decode them (6.0 codes flagged as no-start suspects), clear codes (--clear), show battery voltage + key live PIDs.
• DOESN'T: Ford-enhanced diesel PIDs — ICP, FICM main/sync voltage, IPR%. Those need FORScan. For those numbers tonight, measure at the FICM with a meter.

6.0 no-start priority checklist (from the triage)

The 6.0 needs, to fire: good batteries → FICM ~48V → ICP ~500 psi → fuel → cam/crank signal.

1. Batteries — both. Weak battery → FICM won't boost → no injector fire. Load test; ~12.5V+ at rest, watch it while cranking.
2. FICM voltage while cranking (~48V). #1 6.0 cold no-start cause. <45V is suspect.
3. ICP (injection control pressure) ~500 psi to fire. Leaks: STC fitting, oil rail O-rings, high-pressure oil hoses, IPR/HPOP.
4. Fuel — HFCM lift pump priming, fuel filters, water-in-fuel.
5. CMP/CKP sensors — failed cam sensor = crank, no-start (codes P0340/P0341, P0335/P0336).
6. Glow plugs/relay if cold (won't stop start, but hard start).

Code-driven branches the tool will hint at

• P0335/P0336/P0340/P0341/P0344 → cam/crank sensor path.
• P0611/P1316 or P02xx/P026x injector codes → FICM / injector path.
• P0087/P0148/P0191 → fuel pressure (low-side + high-side oil).
• U0100/U0073/P0606 → module comms / PCM.

Status of this session's work

• Tool built + tested against the real adapter (init, all 3 DTC modes, live PIDs, clear flow).
• DTC parser unit-tested incl. a fixed bug: legacy ISO/PWM multi-frame responses repeat the 43 header (was producing phantom codes) — fixed + regression-tested.
• Pushed to git.jpaul.io/justin/ford-obd, branch main. Files: obd_reader.py, RUN_OBD.bat, README.md, README.txt, handoff.md.

To resume with Claude from the cab

Mention: "6.0 Power Stroke no-start, using the ford-obd tool (git.jpaul.io/justin/ford-obd)". Then paste the tool's full output (codes + live values). Useful to also say: cranks vs. no-crank, hot vs. cold, what changed before it died, and FICM/ICP readings if you metered them.

Open follow-ups (when off the truck)

• FORScan from the CyanLabs mirror once forscan.org is back, for ICP/FICM/IPR PIDs on the same adapter.
• Optional: add a few known Ford Mode-22 enhanced PIDs to the tool (verify PID numbers first).