OBD-II Code
P0689
Severity
Not yet reviewed
Nobody on our side has assessed this code yet, so we are not going to guess at how serious it is.
Can you drive it
We cannot say
Treat it as unknown until a shop reads it with live data. If the check-engine light is FLASHING, stop driving as soon as it is safe to — that means an active misfire, whatever the code.
Indicative cost (USD)
$25–$900
From this code's diagnostic notes. Varies by vehicle, diagnosis, parts, and local labor. This is not a repair quote.
$25 (relay) to $900 (TIPM + programming).
P0689 sets when the PCM's sense circuit on the main power relay reads low — the PCM expected 12V on the sense pin with the relay commanded on and saw something below the threshold (typically under 3-4V).
How a shop works this
Work from evidence to part, not the other way round. A code names a circuit or a symptom; it does not name the part that failed.
Note every code that is set, not just this one.
Codes that appear together usually narrow the cause faster than any one of them read alone.
Read the freeze frame — the conditions the fault was recorded under.
Cold or warm, idle or load, road speed and engine speed. A fault that only appears cold is a different fault from one that only appears under load, even with the same code on the scanner.
Confirm the fault is current rather than history.
Clear the code and see whether it returns under those same conditions. A code that does not come back may have been logged during a repair, a flat battery, or a bad connection that has since been disturbed.
Then follow the diagnostic notes further down this page, in the order they are written.
They are written in the order a shop works this code, cheapest checks first. Where they name a component, inspect its wiring and connector before replacing it.
If the code comes back after a repair, the underlying fault is still there. That is the point to bring in a scanner with live data and freeze-frame, or a shop that has one.
Common symptoms
- Check engine light
Read the full diagnostic procedureP0689 sets when the PCM's sense circuit on the main power relay reads low — the PCM expected 12V on the sense pin with the relay commanded on and saw…
P0689 sets when the PCM's sense circuit on the main power relay reads low — the PCM expected 12V on the sense pin with the relay commanded on and saw something below the threshold (typically under 3-4V). This is closely related to P0688 (open) but indicates the wire is shorted to ground OR the relay contacts have high resistance and only partial voltage is making it through.
Cheapest-first ladder
- Pull and bench-test the relay — coil should be 60-80 ohms, contacts should pass a continuity check with no measurable resistance when energized; any contact resistance above 0.2 ohms means pitted contacts and the relay needs to be replaced.
- Voltage-drop test from the relay output terminal to the PCM sense pin with the relay energized — should be under 0.1V drop; anything higher is wire corrosion, often at a body connector or splice pack.
- Inspect the sense wire for a chafe-to-ground point — these failures cluster at firewall pass-throughs and along the inner fender harness routing. Target threshold: 12V sense relay-on, 0V relay-off, with under 0.1V drop end-to-end on the sense circuit. Expensive-misdiagnosis caveat: the same Honda K-series and Chrysler Pentastar relay-PCM ambiguity applies here — swap the $25 relay and re-run the scan before quoting a $700 PCM, and on the Chrysler platforms specifically, check the TIPM internal relay before condemning anything because the TIPM is a sealed assembly that can fail the sense circuit through internal corrosion regardless of what the bench-test on the external relay shows.
Vehicle-specific patterns2001-2005 Honda K-series (Civic, Accord, CR-V, RSX) throws P0689 alongside P0688 when the main-relay solder joints crack and intermittently short to…
- 2001-2005Honda K-series (Civic, Accord, CR-V, RSX) throws P0689 alongside P0688 when the main-relay solder joints crack and intermittently short to chassis as the PCB flexes — reflow fixes both.
- 2011-2014Chrysler 3.5/3.7/3.6 Pentastar lineup (Town & Country, Grand Caravan, Charger, Wrangler) throws P0689 from TIPM water intrusion via the cowl drain — corrosion bridges the relay output to ground inside the module; the TIPM is the only fix.
- 2007-2014GM full-size trucks throw P0689 from under-dash relay solder failures combined with chafe at the steering column harness.
- 2004-2011Mazda RX-8 throws P0689 when the relay socket terminals corrode enough to drop sense voltage below threshold without fully opening.
- 2003-2008Subaru Forester/Outback with the EJ25 throws P0689 from a known fuse-box water intrusion via the cowl drain (similar mechanism to the Chrysler TIPM).
Estimated repair$25 (relay) to $900 (TIPM + programming).
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