OBD-II Code
P1734
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)
$55–$1,400
From this code's diagnostic notes. Varies by vehicle, diagnosis, parts, and local labor. This is not a repair quote.
P1734 is a Ford-specific code meaning the MLPS is reporting a voltage consistent with the Manual-2 position (~3.6V on the standard six-step ladder) when the PCM/TCM didn't command or expect 2nd gear — the MLPS is stuck on the M2 step, or the wiper is hanging on the M2 contact during shifts through that position.
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 procedureP1734 is a Ford-specific code meaning the MLPS is reporting a voltage consistent with the Manual-2 position (~3.6V on the standard six-step ladder) w…
P1734 is a Ford-specific code meaning the MLPS is reporting a voltage consistent with the Manual-2 position (~3.6V on the standard six-step ladder) when the PCM/TCM didn't command or expect 2nd gear — the MLPS is stuck on the M2 step, or the wiper is hanging on the M2 contact during shifts through that position. This is a narrower variant of P1716/P1717 specifically isolating the 2nd-gear manual range.
Cheapest-first ladder
- Cycle the shifter slowly through all six positions with KOEO and the scan tool watching MLPS voltage — a healthy sensor steps cleanly through 0.5V (P), 1.2V (R), 2.0V (N), 2.8V (D), 3.6V (M2), 4.4V (M1); a sensor stuck on the M2 step will sit at ~3.6V regardless of where the shifter physically is, OR it will hang on 3.6V as you shift past it and only release after a few seconds.
- Inspect for ATF migration in the MLPS connector — fluid bridging contacts inside the sensor body will create a parasitic short to the M2 contact ($0, 10 min).
- Verify the shifter cable and manual valve lever are physically reaching all detents — a worn detent spring inside the trans (rooster comb) can let the manual valve hang in M2 even when the driver shifts to Drive, which is a mechanical issue inside the valve body, not the sensor.
- Confirm the 5V reference and ground at the MLPS are clean — a high-resistance ground will skew every voltage step upward, parking a normally-Drive (2.8V) signal into the M2 (3.6V) band. Expensive-misdiagnosis caveat: P1734 paired with a complaint of 'starts off in 2nd' is often misdiagnosed as MLPS failure when the actual fault is failsafe limp mode — most Ford gearboxes default to 2nd gear in limp mode, and the MLPS code is a downstream symptom; check for solenoid codes (P0750-P0768 family) before chasing the MLPS.
Vehicle-specific patterns1996-2003 Ford Explorer/Mountaineer with the 5R55E and 1997-2011 Ford Ranger with the 5R55E throws P1734 from MLPS contact wear at the M2 wiper posit…
- 1996-2003Ford Explorer/Mountaineer with the 5R55E and 1997-2011 Ford Ranger with the 5R55E throws P1734 from MLPS contact wear at the M2 wiper position — police/fleet Crown Vics see the same wear on the AODE/4R70W.
- 1996-2010F150 and 1996-2014 E150/E250/E350 vans with the AODE/4R70W see P1734 from the same wear pattern plus from manual-lever rooster-comb wear inside the trans (a common rebuild item).
- 1996-2010Mustang with the AODE/4R70W sees P1734 less often because the shifter sees less M2 use. P1734 specifically on a trans that was recently rebuilt usually points at incorrect MLPS calibration or installation orientation.
Estimated repair$55 to $1,400.
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