justin
e15e22a825
obd_reader.py: - Mode 22 plumbing: ELM.mode22() sends a 16-bit PID request, parses both positive (62 ..) and negative (7F 22 NRC) responses. - --ford runs a small TENTATIVE table of community-sourced Ford 6.0 PIDs (ICP/IPR/FICM/EBP/EOT). All printed with raw bytes for verification. - --pid XXXX probes a single PID and prints multiple candidate decodings (u8, u16, mV, temp, duty) so we can eyeball the right scaling. - --watch [N] streams ATRV + module voltage (PID 0142) for N seconds. Designed for capturing voltage sag during cranking. - --scan AAAA-BBBB brute-force scans Mode-22 PIDs with --scan-log PATH for output. Uses fast ELM timing (ATAT2, ATST19) for ~3.5 PIDs/sec. diagnostics/2026-06-29-no-start/: - Captured cranking voltage trace, full Mode-22 scan (1000-14FF -> 46 hits), and a session writeup. Working hypothesis: not batteries, not fuel -- ICP / FICM / CMP. FICM meter test still owed. Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
116 lines
4.9 KiB
Markdown
116 lines
4.9 KiB
Markdown
# 2026-06-29 — 6.0 Power Stroke no-start session
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In-cab diagnostic session using the `ford-obd` tool on the truck.
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Charger on "12V Hi" was attached for most of the session.
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## Symptoms
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- Cranks **fast** (starter spins the engine normally)
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- **Zero combustion event** — no sputter, no cough, no kickback
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- HFCM lift pump heard priming on key-RUN and shutting off normally
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- Battery at OBD port: 11.2 – 12.7V key-RUN (varied with charger state)
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## Codes pulled (multiple reads, slight variation between reads)
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| Mode | Code | Description |
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|---|---|---|
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| Stored (03) | `C0300` | (chassis — not engine, not in our DB) |
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| Pending (07) | `C0700` / `C0701` | (chassis — alternated between reads) |
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| Pending (07) | `P0113` | IAT circuit HIGH — sensor wiring, not a no-start |
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| Permanent (0A) | `C3F0A` | (chassis — not engine) |
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No engine P-codes, no FICM codes, no injector codes, no CMP/CKP codes.
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## What we ruled out
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- **Batteries as primary cause** — cranks fast and voltage held adequately
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(see `watch-cranking.log`). Bus sagged to 10.8–11.2V during ~11s crank,
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borderline-low but not catastrophic. Healthy starter spin means batteries
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have current to give.
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- **Fuel supply** — HFCM lift pump audibly primes and shuts off correctly
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on key-RUN.
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- **Compression / mechanical** — fast even cranking, would feel different
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with a low-compression cylinder.
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## Working hypothesis (in order of suspicion)
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1. **ICP / high-pressure oil leak** — STC fitting is the classic 6.0 culprit
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for "cranks great, won't fire, no codes". Need ≥500 psi ICP to fire even
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one injector.
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2. **FICM weakness** — should boost to ~48V. Sometimes doesn't throw a code
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even when failing. **Not yet measured** — see open items.
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3. **CMP sensor** — would usually throw P0340/P0341 but not always.
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## What we did with the tool this session
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- Pulled DTCs across all 3 modes (multiple times).
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- Captured cranking voltage with `--watch 30` (see `watch-cranking.log`):
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- Pre-crank: bus 11.7→12.1V, VPCM 12.39→12.71V
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- Cranking (~11s): bus 10.8–11.2V, VPCM 11.32–11.70V
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- Recovery: bus 11.8–12.2V, VPCM stopped responding (`?`) — possible
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PCM brief recovery state after the dip.
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- Ran first attempt at Mode-22 probes (`--ford`) with community-sourced
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PIDs (ICP=1209, FICM=1228/1229/122A, IPR=120B, etc.). **All returned
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"no response."** Either the PCM uses different PID numbers, or these
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values live on Ford's SCP bus and aren't gatewayed to OBD-CAN.
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- Brute-force scanned PIDs `0x1000-0x14FF` (1280 PIDs, ~6 min, 46 hits).
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See `mode22-scan-hits.txt`. Data is noisy because **multiple modules on
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the bus answer the same query** — positive responses from PCM mixed
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with negative-response bytes (`7F 22 12`, `7F 22 31`) from other modules.
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## Interesting PIDs from the scan to verify next session
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Cleanest-looking PCM-side responses worth re-probing individually
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(with normal timing, `python obd_reader.py --pid XXXX`):
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```
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1310 2 1C 92 (was 1C 69 earlier — value changes; maybe a counter?)
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1440 2 01 89 = 393
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1442 2 01 88 = 392 ← three closely-spaced ~390 values
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1445 2 01 8F = 399 suggests a related sensor cluster
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1446 2 00 16 = 22
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1447 2 00 34 = 52
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1448 2 00 11 = 17
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11B3 1 02
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11B4 2 00 00
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11BA 2 FF 5C
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```
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Likely scaling guesses:
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- raw / 100 → fits if these are voltage-tenths or pressure-tenths
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- raw / 1000 → if mV (0.393V plausible for sensor outputs)
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- raw - some offset → temperature
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To know what each one *is*, compare against a known measurement:
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- Run `--pid 1440` with engine off, write down value.
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- Get engine running (eventually), write down value.
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- Change condition, watch which PIDs move.
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## Open items / what's next
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1. **FICM meter test was started but no readings reported back yet.**
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Measure M / S / L on the FICM body, key-ON and during a (short) crank:
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- M (Main) target ~48V cranking, <45V suspect, <40V dead
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- S (Sync) target ~48V cranking
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- L (Logic) target ~12V (mirrors battery)
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2. **Visual under-engine check** for STC-fitting oil leak (wet/oily mess
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at the rear of the engine, around the turbo / bell housing).
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3. **Verify scan-hit PIDs.** Re-probe the clean ones above with
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`--pid XXXX` to get uncontaminated readings, log them against known
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conditions.
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4. **Try addressing other modules with `ATSH`** — particularly the FICM
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on its CAN address if it has one (uncertain on 6.0 — likely on SCP).
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5. Try **FORScan** when forscan.org / CyanLabs mirror is back, on the
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same CH340 adapter, to capture FORScan's actual PID requests for
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ICP/FICM/IPR. That gives us the ground truth.
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## Tool state at end of session
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`obd_reader.py` now has:
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- `--ford` — try the (tentative) Ford 6.0 Mode-22 PID table
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- `--pid XXXX` — one-shot probe of any 16-bit Mode-22 PID
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- `--watch [N]` — stream ATRV + VPCM for N seconds (default 20)
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- `--scan AAAA-BBBB` + `--scan-log PATH` — brute-force scan a PID range
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All work on the CH340 ELM327 v1.5 clone at 38400 baud, HS-CAN switch.
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