P0731 on Ford: How to Diagnose & Fix
Gear 1 Incorrect Ratio
2 Ford models · 4 documented issues · 3 critical · $150-$4,500 repair
P0731 on Ford by model: symptoms, diagnosis and fix
On the F-150, P0700 is a generic "MIL request" companion code the PCM stores whenever the transmission control strategy has logged an underlying transmission fault — it points to a problem but never names it by itself. On the extremely common 6R80 six-speed automatic (F-150 2011-2020, plus the 6R80 in Expedition/Navigator), the fault that most often drives P0700 is a failing internal molded leadframe (the plastic wiring harness/module inside the transmission that houses the output/input/turbine speed sensors and connects the shift solenoids to the valve body, Ford p/n AL3Z-7G276-D). As the leadframe's soldered connections and speed sensors degrade, the PCM sets P0700 alongside the real culprit codes — typically output-speed-sensor and gear-ratio codes such as P0720, P0722, P0731, P0715 and/or P1500. Note the mid-production architecture change: on 2009-2010 6R80 units the TCM lives in a separate leadframe/Mechatronic module that talks to the PCM (so P0700 can also accompany a lost-communication U-code), while on 2011+ trucks Ford integrated the TCM logic into the PCM and companion codes store directly there. Newer F-150s (2017+) use the 10R80 10-speed, where P0700 more often stems from valve-body/solenoid and TCM software issues rather than a leadframe.
Common Symptoms
- Check-engine and/or wrench (transmission) warning light on
- Harsh, delayed, or erratic shifting
- Transmission stuck in a single gear (limp mode)
- Speedometer dropping to zero or reading intermittently
- Sudden unintended downshift into low gear at speed (rear-wheel lockup risk)
- No/late upshifts and reduced power
How to Fix
Never replace parts off P0700 alone — pull the stored companion codes first. On a 6R80 F-150 showing P0700 with speed-sensor/ratio codes (P0720/P0722/P0731/P0715/P1500) and a wrench light, the accepted repair is to drop the transmission pan and replace the internal molded leadframe assembly (AL3Z-7G276-D), refill with Mercon LV, then clear codes and road-test. Eligible 2011-2013 F-150 (and 2012-2013 Expedition/Navigator) 6R80 trucks are covered FREE under Ford Customer Satisfaction Program 19N01, which extends leadframe coverage to 10 years/150,000 miles — check VIN eligibility before paying. A related PCM reprogram (recall 19S07) prevents the dangerous unintended downshift-to-first. If the leadframe checks out, diagnose the specific companion code (solenoid, valve body, wiring/connector corrosion, or low/burnt fluid). After any valve-body or solenoid work the TCM must be reflashed with the correct solenoid-body strategy or the truck will shift harshly. On 10R80 trucks, address the named companion code (often a shift-solenoid or valve-body concern) and update TCM software.
Sources for this issue (1)
The 10R80 10-speed automatic (introduced on the 2017 F-150) is widely reported to shift harshly: jerking, clunking, banging on the 1-2 and 2-3 shifts, hesitation, gear hunting, and occasional limp-mode with a 'Transmission Not in Park' or 'drive mode not available' message. Many trucks also exhibit a torque-converter lockup-clutch shudder felt as a vibration around 30-45 mph. Root causes traced in later TSBs include adaptive-calibration mismatch during break-in, CDF drum bushing migration, and valve-body bore wear/scoring. A class action (O'Connor v. Ford, N.D. Illinois) covers the defect.
Common Symptoms
- Harsh 1-2/2-3 upshifts that jerk or clunk
- Loud bang/clunk when starting the truck
- Hesitation, gear hunting, or slipping
- Vibration/shudder at 30-45 mph (torque-converter lockup)
- Limp mode or 'drive mode not available' message
How to Fix
Start with a Ford PCM/TCM reflash to the latest calibration and an adaptive-learning relearn drive cycle (early TSBs 18-2079/18-2274, later 23-2250 superseded by 24-2046). For shudder, a transmission fluid service with Mercon ULV plus friction modifier helps. Persistent harsh shifts with valve-body bore damage require main control valve body replacement (TSB 22-2428). Severe cases need converter or transmission overhaul.
Sources for this issue (1)
The 6R80 six-speed automatic (2009-2017 F-150) is generally durable but is widely reported for a harsh, banging 1-2 upshift and erratic/flaring shifts, with thousands of NHTSA complaints. The internal solenoid body 'lead frame' (the mechatronic wiring carrier) can crack or develop failing solenoid calibration, and the adapt strategy struggles to relearn after service. The classic symptom is a 1-2 shift so abrupt owners describe it as a jolt that could 'knock a cup of coffee out of your hand.' Towing, worn fluid, and never-serviced 'lifetime' fluid accelerate the problem. It is a top transmission search for this generation.
Common Symptoms
- Harsh or banging 1-2 upshift
- Flaring or erratic shifts
- Delayed engagement into drive/reverse
- Shudder under load or while towing
- Transmission fault / wrench light in severe cases
How to Fix
Start with a full fluid-and-filter service using Mercon LV (the 'lifetime fill' should still be serviced ~every 60k, sooner with towing). Have the dealer flash the PCM/TCM to the latest calibration — Ford released shift-quality calibration updates that fix many harsh/delayed-engagement complaints as the first repair. Persistent harsh shifting or specific solenoid codes call for a solenoid body / lead-frame replacement (Ford solenoid body assembly, commonly cross-referenced as Sonnax/aftermarket units). A TCM adaptive (keep-alive) reset and relearn is required after repairs. Fluid service $200-$400; solenoid body $600-$1,200 installed; valve-body/rebuild far more.
What you need to fix it
Only diagnosis- and fitment-reviewed repair parts are linked here.
- 6R80 automatic transmission filter (2011-2017 F-150, 3.5L EcoBoost / 3.7L / 5.0L / 6.2L)OEMBL3Z-7A098-ACross-refMotorcraft FT-188, WIX WL10377, Baldwin 20029$22–$49
Use this filter for 2011-2017 trucks with the 3.5L EcoBoost, 3.7L Ti-VCT, 5.0L Coyote or 6.2L and the 6R80. It is NOT the filter for 2015-2017 2.7L EcoBoost/3.3L trucks (those use FL3Z-7A098-A/-B) nor for 2018+ 10R80 trucks (HL3Z-7A098-A).
- 6R80 automatic transmission filter (2009-2010 F-150, 6.2L / 4.6L / 5.4L with 6R80)OEM7L1Z-7A098-A$34–$56
Within this issue's engine list only the 6.2L (2010 Raptor/Harley) falls in 2009-2010 - the 3.5L EcoBoost, 3.7L and 5.0L did not arrive until
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Sources for this issue (1)
P0731 code reference
General diagnostic-code context. The code alone does not confirm a cause for your vehicle; use the applicable issue card and its sources.
Frequently asked questions
What does P0731 mean on a Ford?
P0731 stands for "Gear 1 Incorrect Ratio." This code means the Transmission/Powertrain Control Module detected an incorrect gear ratio in 1st gear. The module compares input (engine/turbine) speed to output shaft speed; when the car is commanded into 1st but the calculated ratio doesn't match the expected value, P0731 sets. This points to slipping, an incorrect shift, or a hydraulic/mechanical problem rather than just an electrical fault. You may feel slipping, harsh or delayed engagement, or the transmission may go into a limited 'limp' mode. On Ford it is documented across 2 models: Transit, F-150.
What are the most common causes of P0731?
The most common causes of P0731 are: Low or degraded/burnt transmission fluid, Slipping clutch packs or worn friction components, Stuck or faulty shift solenoid affecting 1st gear, Internal hydraulic leak / valve body fault, Worn or failing torque converter, Faulty input or output speed sensor, Mechanical wear (planetary gears, bands) inside the transmission. The specific cause varies by vehicle.
How much does it cost to fix P0731 on a Ford?
Published repair estimates on Ford range from $150 to $4,500 depending on the model and root cause. If an issue mentions a recall or campaign, check your VIN with the manufacturer or NHTSA and confirm eligibility and coverage with a dealer.
Looking for P0731 on a different make?
View P0731 across all makes →Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.