Code
P1911
Generic
P — Powertrain
VFS B Pressure Output Failed Low
AI status
Completed
Completed
100%
Causes
- Low transmission fluid level or degraded fluid
- Restricted or blocked hydraulic passage in the valve body
- Failed or sticking VFS B solenoid (stuck open/closed or internal leak)
- Open/short/poor connection in the solenoid wiring or connector (including corroded pins)
- Faulty ground or supply to the solenoid (blown fuse, relay, wiring)
- Faulty pressure sensor or inaccurate feedback to the controller
Symptoms
- Transmission warning lamp (MIL) or gearbox warning illuminated
- Harsh, delayed or erratic shifting
- Transmission may be stuck in limp/reduced-gear mode
- Slipping or poor engagement of affected gear(s)
- Stored P1911 code often accompanied by related transmission DTCs
What to check
- Read and record freeze frame and all stored/pendant transmission codes
- Check transmission fluid level and condition at operating temperature; look for contamination or burnt smell
- Inspect VFS B electrical connector and wiring for damage, corrosion, loose pins or chafing
- Check for related blown fuses or faulty relay in transmission control circuits
- Measure solenoid coil resistance and compare to manufacturer spec
- Back-probe connector to observe control voltage/PWM and supply voltage with scanner or oscilloscope while commanding the solenoid
Signal parameters
- Solenoid coil resistance: typically in the low tens of ohms (example 10–30 Ω) — check OEM spec for vehicle
- Supply voltage to solenoid: near battery voltage (approx. 11–14 V) when powered by relay/fuse
- Control signal: PWM duty cycle from 0–100% (varies by command) or voltage modulation; use scope for waveform verification
- Expected behavior: commanded increase in duty should produce corresponding increase in hydraulic pressure; actual pressure should follow within manufacturer tolerance
Diagnostic algorithm
- Connect a scan tool, record freeze frame and related codes. Note transmission temperature and conditions when code set.
- Check transmission fluid level and condition; remedy low/contaminated fluid if found and clear codes to test.
- Visually inspect VFS B connector and wiring for damage, corrosion or poor connection; repair any faults.
- With ignition off, measure static coil resistance of VFS B and compare to spec. Replace solenoid if out of range.
- Back-probe the solenoid connector. With engine running and TCM commanding, observe supply voltage and control signal (use a scope if possible). Verify PWM duty changes when commanding VFS B on/off via scan tool.
- Perform a hydraulic pressure test at the designated pressure test port while commanding VFS B; compare measured pressure to expected response. Low/no change indicates hydraulic or solenoid failure.
- If electrical tests pass but pressure is low, remove valve body or solenoid assembly to inspect for internal contamination, sticking spools, or valve body damage; clean or replace as required.
- If a replacement solenoid or repairs are made, clear codes and perform a road test under varied conditions to confirm repair. Re-scan for recurrence.
- Safety note: use proper supports (jack stands), follow manufacturer procedures for fluid handling and pressure testing.
Likely causes
- Faulty or sticking VFS B solenoid
- Open/short/poor connector or wiring to VFS B
- Low or contaminated transmission fluid
- Restricted hydraulic passage or valve body problem
Fault status
Status
P1911 — VFS B Pressure Output Failed Low. Commanded pressure output for VFS B is lower than expected; check solenoid, wiring, fluid level/condition, and hydraulic passages.
Repair difficulty: Medium
Diagnostic time: 1.5-3.0 hours
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Code
P1911
Other
P — Powertrain
VFS B Pressure Output Failed Low
AI status
Completed
Completed
100%
Causes
- Low transmission fluid level or degraded fluid
- Restricted or blocked hydraulic passage in the valve body
- Failed or sticking VFS B solenoid (stuck open/closed or internal leak)
- Open/short/poor connection in the solenoid wiring or connector (including corroded pins)
- Faulty ground or supply to the solenoid (blown fuse, relay, wiring)
- Faulty pressure sensor or inaccurate feedback to the controller
Symptoms
- Transmission warning lamp (MIL) or gearbox warning illuminated
- Harsh, delayed or erratic shifting
- Transmission may be stuck in limp/reduced-gear mode
- Slipping or poor engagement of affected gear(s)
- Stored P1911 code often accompanied by related transmission DTCs
What to check
- Read and record freeze frame and all stored/pendant transmission codes
- Check transmission fluid level and condition at operating temperature; look for contamination or burnt smell
- Inspect VFS B electrical connector and wiring for damage, corrosion, loose pins or chafing
- Check for related blown fuses or faulty relay in transmission control circuits
- Measure solenoid coil resistance and compare to manufacturer spec
- Back-probe connector to observe control voltage/PWM and supply voltage with scanner or oscilloscope while commanding the solenoid
Signal parameters
- Solenoid coil resistance: typically in the low tens of ohms (example 10–30 Ω) — check OEM spec for vehicle
- Supply voltage to solenoid: near battery voltage (approx. 11–14 V) when powered by relay/fuse
- Control signal: PWM duty cycle from 0–100% (varies by command) or voltage modulation; use scope for waveform verification
- Expected behavior: commanded increase in duty should produce corresponding increase in hydraulic pressure; actual pressure should follow within manufacturer tolerance
Diagnostic algorithm
- Connect a scan tool, record freeze frame and related codes. Note transmission temperature and conditions when code set.
- Check transmission fluid level and condition; remedy low/contaminated fluid if found and clear codes to test.
- Visually inspect VFS B connector and wiring for damage, corrosion or poor connection; repair any faults.
- With ignition off, measure static coil resistance of VFS B and compare to spec. Replace solenoid if out of range.
- Back-probe the solenoid connector. With engine running and TCM commanding, observe supply voltage and control signal (use a scope if possible). Verify PWM duty changes when commanding VFS B on/off via scan tool.
- Perform a hydraulic pressure test at the designated pressure test port while commanding VFS B; compare measured pressure to expected response. Low/no change indicates hydraulic or solenoid failure.
- If electrical tests pass but pressure is low, remove valve body or solenoid assembly to inspect for internal contamination, sticking spools, or valve body damage; clean or replace as required.
- If a replacement solenoid or repairs are made, clear codes and perform a road test under varied conditions to confirm repair. Re-scan for recurrence.
- Safety note: use proper supports (jack stands), follow manufacturer procedures for fluid handling and pressure testing.
Likely causes
- Faulty or sticking VFS B solenoid
- Open/short/poor connector or wiring to VFS B
- Low or contaminated transmission fluid
- Restricted hydraulic passage or valve body problem
Fault status
Status
P1911 — VFS B Pressure Output Failed Low. Commanded pressure output for VFS B is lower than expected; check solenoid, wiring, fluid level/condition, and hydraulic passages.
Repair difficulty: Medium
Diagnostic time: 1.5-3.0 hours
Similar codes
Repair manuals
Brands with available manuals
7,849
The library contains 7,849 repair and diagnostic manuals. Choose a brand to open the full manual tree by year, model and trim.
Your experience will help others
+100 karma for a short comment :)
Was this AI description helpful?
Your feedback helps improve AI descriptions.
👍 Like
0
👎 Dislike
0
Send to email