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
- **DTCs**: stored / pending / permanent (modes 03/07/0A), with 6.0-relevant
  codes flagged as no-start suspects. `--clear` erases (mode 04).
- **Generic live PIDs**: RPM, ECT, IAT, MAP, engine load, module voltage, ATRV.
- **`--ford`**: Mode-22 read of the **VERIFIED** Ford 6.0 PID set — ICP, EBP,
  MAP, BARO, MGP (boost), EOT, gear, TSS, plus the documented FICM trio
  (`09D0` Main, `09CF` Logic, `09CE` Vehicle V) and `09CD` Sync. Full PID
  research + sources in
  [diagnostics/2026-06-29-no-start/pid-research.md](diagnostics/2026-06-29-no-start/pid-research.md).
- **`--crank`**: dedicated cranking monitor — large ICP readout + trace of ICP,
  FICM Main, battery, RPM. **This is the no-start mode.**
- **`--dash`**: real-time gauge dashboard. Presets: `--dash crank` (cranking),
  `--dash full` (everything). Add `--dash-log run.csv` to capture a CSV trace.
- **`--pid XXXX`**: one-shot probe of any 16-bit Mode-22 PID; prints raw bytes
  plus a few candidate decodings.
- **`--scan AAAA-BBBB`** (with optional `--scan-log PATH`): brute-force a PID
  range. Use for hunting new PIDs.

What still needs FORScan: **desired ICP** (`ICP_DES`) and a labeled FICM-Sync
yes/no gauge — neither has a published Mode-22 DID. Everything else for
no-start diagnosis is reachable through this tool now.

## 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.
- **2026-06-29 in-cab session:** added `--watch`, `--ford`, `--pid`, and `--scan`
  modes. Captured cranking voltages + ran a Mode-22 brute scan (46 PIDs hit).
  Full session writeup + raw data in [diagnostics/2026-06-29-no-start/](diagnostics/2026-06-29-no-start/README.md).
  **Headline:** FICM measured >48V (healthy). Truck **starts on ether every
  time** and runs/idles fine until shut off — then needs ether again. That
  signature ⇒ **high-pressure oil (ICP) bleed-off during cranking** — STC
  fitting / oil rail O-rings / HPOP-related. Compression, FICM, CMP/CKP,
  fuel supply all confirmed good.
- **2026-06-30 desktop session:** multi-agent PID research workflow corrected
  the Mode-22 table — the original 12xx guesses were wrong addresses, not a
  bus problem. Verified PID set now in `obd_reader.py`; reasoning + sources
  in [pid-research.md](diagnostics/2026-06-29-no-start/pid-research.md).
  Added `--dash` (real-time gauges) and `--crank` (no-start monitor).
- **2026-06-30 ICP crank test:** ran `--crank` on the truck — **peak ICP
  376 psi, below the 500 psi firing threshold**. Direct empirical
  confirmation of the high-pressure oil bleed hypothesis. FICM min 48.0 V
  (healthy), battery min 10.3 V (adequate). Output captured in
  [crank-test-2026-06-30.txt](diagnostics/2026-06-29-no-start/crank-test-2026-06-30.txt).
  Next: physical inspection (IPR valve first, then STC fitting, then
  oil rail O-rings).
- Pushed to `git.jpaul.io/justin/ford-obd`, branch `main`.

## 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.

## To resume at the truck (2026-06-30 state)

The diagnosis is now **empirically confirmed** — `--crank` measured peak
ICP 376 psi (need ~500 psi to fire). High-pressure oil bleeds off during
cranking; HPOP outruns the leak once running. The 376 psi reading suggests
a **partial** leak rather than a fully blown STC fitting. Physical
inspection, cheap-and-easy first:

1. **Pull the IPR valve** (~15 min, ~$0). Bolted into the back of the
   HPOP, top-rear of engine under the turbo. Inspect screen for debris,
   pintle/seat for wear, O-rings for cuts. A leaky IPR seat causes
   exactly this "partial pressure" symptom.
2. **STC fitting visual** — between the heads under the turbo. Look for
   wet/oily film at the fitting joint. Ford TSB; classic 6.0 wear item.
3. **Pull valve covers** and inspect high-pressure oil rail O-rings on
   each head. Bigger job but common 6.0 leak path.
4. (Once a repair is attempted, re-run `--crank` — peak ICP should jump
   to 500+ if the fix worked.)

OBD-side follow-ups (lower priority now that we have the answer):
- Probe the FICM 09xx family: `--pid 09D0` (Main, ~48V), `--pid 09CF`
  (Logic, ~12V), `--pid 09CE` (Vehicle V), `--pid 09CD` (Sync).
- Widen brute scan: `--scan 0900-09FF --scan-log scan-09xx.txt`
  and `--scan 1600-16FF --scan-log scan-16xx.txt`.

## Open follow-ups
Detailed action list lives in
[pid-research.md §5](diagnostics/2026-06-29-no-start/pid-research.md). Highlights:
- Validate the documented-but-untested PIDs (`09D0/09CF/09CE/09CD`, `16AD`,
  `1434`, `1172`, `1672`, `096D`, `099F`) by reading them on-vehicle.
- Sanity-check IPR (`1434`) against expected ranges: KOEO ~14–15 %,
  cranking ~30–40 %, warm idle ~25–30 %.
- Calibrate `16C1` fuel-level scaling per-truck (published divisors misread).
- FORScan via CyanLabs mirror — only path to `ICP_DES` and a labeled FICM
  Sync gauge.