DOCUMENTED DIAGNOSTIC CONTEXT
Diagnostic code articles — Page 35.
Understand what the recorded fault means, which findings change the diagnosis, and what the cited documentation can confirm. Each article states the system or vehicle scope it covers.
Some sources leave details unresolved. Those articles include a visible source note; a code match alone does not establish applicability to your vehicle.
Generic OBD-II
P2780
Downshift circuit low has a printed threshold conflict to resolve
PowertrainRead article
Generic OBD-II
P2781
A downshift input-high fault concerns voltage, not a held paddle
PowertrainRead article
Generic OBD-II
P2796
Auxiliary transmission-pump motor circuit is diagnosed open
PowertrainRead article
Generic OBD-II
P2797
CVT auxiliary pump supplies inadequate pressure during an auto-stop event
PowertrainRead article
Generic OBD-II
P2798
Auxiliary transmission-pump control circuit is electrically low
PowertrainRead article
Generic OBD-II
P2799
Auxiliary transmission-pump control circuit detects unwanted power
PowertrainRead article
Generic OBD-II
P279A
transfer-case high-range command disagrees with measured ratio
PowertrainRead article
Generic OBD-II
P279B
transfer-case low-range command disagrees with measured ratio
PowertrainRead article
Generic OBD-II
P279C
transfer-case range information that needs a careful cross-check
PowertrainRead article
Generic OBD-II
P27A7
Solenoid A characterization data does not match a valid programmed set
PowertrainRead article
Generic OBD-II
P27A8
Solenoid B data fails the transmission controller’s compatibility check
PowertrainRead article
Generic OBD-II
P27A9
Solenoid C calibration data fails completeness or integrity checks
PowertrainRead article
Generic OBD-II
P27AA
Solenoid D characterization is not accepted as correctly programmed
PowertrainRead article
Generic OBD-II
P27AB
Solenoid E characterization data is missing, incompatible or invalid
PowertrainRead article
Generic OBD-II
P27AC
Solenoid F stored characterization does not pass startup validation
PowertrainRead article
Generic OBD-II
P27AD
pressure-control solenoid G characterization data is invalid
PowertrainRead article
Generic OBD-II
P27AE
pressure-control solenoid H characterization fails validation
PowertrainRead article
Generic OBD-II
P27B2
Range-control supervision can involve parking-lock safety
PowertrainRead article
Generic OBD-II
P27B3
The transmission architecture determines what this supervision code means
PowertrainRead article
Generic OBD-II
P27B4
Gear-direction supervision distinguishes launch from wrong-direction events
PowertrainRead article
Generic OBD-II
P27B5
Overspeed protection and ratio plausibility are different supervision branches
PowertrainRead article
Generic OBD-II
P27B6
Transmission tie-up protection and deceleration supervision need different context
PowertrainRead article
Generic OBD-II
P27B9
Shift solenoid two stuck-off is checked with controlled rod movements
PowertrainRead article
Generic OBD-II
P27BA
A stuck-on shift valve is inferred from two rods moving differently
PowertrainRead article
Generic OBD-II
P27BD
Shift valve two open-load is assessed with the output off
PowertrainRead article
Generic OBD-II
P27BF
Shift valve two circuit-low concerns driver feedback during switching
PowertrainRead article
Generic OBD-II
P27C0
Shift valve two circuit-high has a shutdown cross-circuit check too
PowertrainRead article
Generic OBD-II
P27C1
Valve three stuck-off needs a second path to validate rod feedback
PowertrainRead article
Generic OBD-II
P27C2
Valve three stuck-on is a paired rod-response pattern
PowertrainRead article
Generic OBD-II
P27C5
An open valve-three circuit is evaluated before hydraulic conclusions
PowertrainRead article
Generic OBD-II
P27C7
Valve-three low-circuit diagnosis requires its electrical test context
PowertrainRead article
Generic OBD-II
P27C8
Valve-three circuit high can be retained from a shutdown test
PowertrainRead article
Generic OBD-II
P27C9
Valve-four stuck-off compares failed motion with a working alternate path
PowertrainRead article
Generic OBD-II
P27CA
Valve-four stuck-on requires unexpected travel and partner relaxation
PowertrainRead article
Generic OBD-II
P27CD
Valve-four open-load uses the circuit’s off-state response
PowertrainRead article
Generic OBD-II
P27CF
Valve-four circuit low is an electrical report, not a hydraulic verdict
PowertrainRead article
Generic OBD-II
P27D0
Valve-four high can also mean a shutdown interaction with another output
PowertrainRead article
Generic OBD-II
P27D1
Valve five needs current-profile evidence because no alternate path exists
PowertrainRead article
Generic OBD-II
P27D2
Valve-five stuck-on uses a larger single-rod movement criterion
PowertrainRead article
Generic OBD-II
P27D5
Valve-five open-load remains an electrical off-state test
PowertrainRead article
Generic OBD-II
P27D7
Valve-five low-circuit classification must be separated from stuck-off behavior
PowertrainRead article
Generic OBD-II
P27D8
Valve-five circuit high has two distinct event histories
PowertrainRead article
Generic OBD-II
P27EB
mode-valve A position signal occupies an illegal voltage band
PowertrainRead article
Generic OBD-II
P27EC
mode-valve A position does not follow its commanded state
PowertrainRead article
Generic OBD-II
P27ED
mode-valve A position circuit voltage is too low
PowertrainRead article
Generic OBD-II
P27EE
mode-valve A position signal exceeds its electrical limit
PowertrainRead article
Generic OBD-II
P27EF
An invalid middle-band voltage can produce a circuit-open result
PowertrainRead article
Generic OBD-II
P27F0
Mode-valve feedback fails to follow a range command
PowertrainRead article
Generic OBD-II
P27F1
Low range-position feedback can represent more than a ground short
PowertrainRead article
Generic OBD-II
P27F2
Range-position circuit high is not a request for a higher gear
PowertrainRead article
Generic OBD-II
P2801
Range sensor B frequency must be checked separately from its position duty cycle
PowertrainRead article
Generic OBD-II
P2802
Internal transmission range sensor B has a low PWM-circuit signal
PowertrainRead article
Generic OBD-II
P2803
Range sensor B signal is high from a power short or an open path
PowertrainRead article
Generic OBD-II
P2804
Confirm Ford’s general B-circuit classification before assuming intermittency
PowertrainRead article
Generic OBD-II
P2805
Independent range-sensor channels disagree after duty-cycle adjustment
PowertrainRead article
Generic OBD-II
P2808
A differential valve stuck-off diagnosis combines pressure and current-profile tests
PowertrainRead article
Generic OBD-II
P2809
Differential valve stuck-on requires pressure despite a zero-current command
PowertrainRead article
Generic OBD-II
P2812
pressure-control solenoid G electrical circuit is open
PowertrainRead article
Generic OBD-II
P2814
pressure-control solenoid G circuit shorted to ground
PowertrainRead article
Generic OBD-II
P2815
pressure-control solenoid G circuit shorted to supply
PowertrainRead article
Generic OBD-II
P2817
GR10 torque-converter clutch fails to achieve commanded coupling
PowertrainRead article
Generic OBD-II
P2818
GR10 torque-converter clutch remains coupled when commanded off
PowertrainRead article
Generic OBD-II
P281B
pressure-control solenoid H electrical control path is open
PowertrainRead article
Generic OBD-II
P281D
why solenoid H circuit-low can also mean an open circuit
PowertrainRead article
Generic OBD-II
P281E
solenoid H voltage-high diagnosis depends on valve mapping
PowertrainRead article
Generic OBD-II
P2820
a documented park-lock valve stuck-off monitor
PowertrainRead article
Generic OBD-II
P2821
how a park-lock valve is diagnosed hydraulically stuck on
PowertrainRead article
Generic OBD-II
P2824
T93 default-disable valve open-circuit detection
PowertrainRead article
Generic OBD-II
P2826
solenoid J circuit-low and the T87a open-circuit exception
PowertrainRead article
Generic OBD-II
P2827
what solenoid J circuit-high actually identifies
PowertrainRead article
Generic OBD-II
P2829
Selector pilot stuck-off is distinguished from a selector spool fault
PowertrainRead article
Generic OBD-II
P282A
Selector pilot stuck-on needs both wrong-route movement and a failed profile
PowertrainRead article
Generic OBD-II
P282D
Selector pilot open-load is an off-state electrical check
PowertrainRead article
Generic OBD-II
P282F
Selector pilot circuit low uses driver evidence, not rod movement
PowertrainRead article
Generic OBD-II
P2830
Selector pilot high can originate in a shutdown cross-output test
PowertrainRead article
Generic OBD-II
P2832
Rod-one plausibility is checked against speed evidence and alternate actuation
PowertrainRead article
Generic OBD-II
P2833
Rod-one circuit low includes missing pulses or an undersized duty cycle
PowertrainRead article
Generic OBD-II
P2834
Rod-one circuit high can be a missing-pulse or duty-cycle fault
PowertrainRead article
Generic OBD-II
P2835
Rod-one intermittent code checks digital frequency, not just dropouts
PowertrainRead article
Generic OBD-II
P2837
Rod-two consistency uses independent gear evidence before blaming position
PowertrainRead article
Generic OBD-II
P2838
Rod-two electrical low is about pulse behavior, not fork travel
PowertrainRead article
Generic OBD-II
P2839
Rod-two high requires pulse-loss or excessive-duty evidence
PowertrainRead article
Generic OBD-II
P283A
Rod-two intermittent feedback is monitored through its frequency
PowertrainRead article
Generic OBD-II
P283C
Rod-three consistency is tied to the even-clutch speed references
PowertrainRead article
Generic OBD-II
P283D
Rod-three circuit low must be read with its reference-supply status
PowertrainRead article
Generic OBD-II
P283E
Rod-three high is a waveform-quality fault on the VREF2 group
PowertrainRead article
Generic OBD-II
P283F
Rod-three intermittent diagnosis evaluates signal timing
PowertrainRead article
Generic OBD-II
P2841
Rod-four plausibility depends on learned position and even-side speed checks
PowertrainRead article
Generic OBD-II
P2842
Rod-four circuit low can mean missing transitions or low duty
PowertrainRead article
Generic OBD-II
P2843
Rod-four circuit high has two distinct digital-signal routes
PowertrainRead article
Generic OBD-II
P2844
Rod-four intermittent feedback is a frequency-window check
PowertrainRead article
Generic OBD-II
P284D
Rod-one drift can be detected directly or through repeated correction
PowertrainRead article
Generic OBD-II
P284E
Repeated rod-two corrections can explain an unrequested-movement code
PowertrainRead article
Generic OBD-II
P284F
Rod-three drift uses even-side gear evidence and correction history
PowertrainRead article
Generic OBD-II
P2850
Rod-four unrequested movement can be a persistent control burden
PowertrainRead article
Generic OBD-II
P2853
Clutch-one pressure discharge performance means pressure below the model here
PowertrainRead article
Generic OBD-II
P2854
Clutch-two low pressure must be compared with what the model expects
PowertrainRead article
Generic OBD-II
P2855
Clutch-one charge performance includes excess pressure near the hold state
PowertrainRead article
Generic OBD-II
P2856
Clutch-two pressure charge performance depends on its control state
PowertrainRead article
Generic OBD-II
P2864
Why rod 5 position can disagree with an engaged gear
PowertrainRead article
These are code references, not a list of confirmed faults on every vehicle. Read the source and applicability notes, then match the exact vehicle, year, engine and scan report.