Code
B1243
ALFA ROMEO
B — Body
Fast window descent switch short to positive
Views:
UK: 3
EN: 6
RU: 1
AI status
Completed
Completed
100%
Causes
- Shorted switch wiring to battery positive
- Damaged or chafed harness contacting a power feed
- Faulty fast descent (auto down) switch with internal short
- Corroded or contaminated connector causing unintended positive feed
- Failed body control module (BCM) input or internal hardware fault
- Aftermarket accessories or recent repairs that disturbed wiring
Symptoms
- Auto (one‑touch) window down function not working
- Intermittent or permanent inability to lower the affected window automatically
- Possible illumination of a related body/control warning or message
- Window may still operate in manual/hold mode if allowed by design
- DTC B1243 stored and can be retrieved by diagnostic tool
What to check
- Confirm code with a suitable diagnostic scanner and record freeze frame/live data
- Visual inspection of door harness at hinge, connectors and switch for damage, corrosion or pin pushed out
- Check related fuses and relays for the power windows circuit
- Disconnect the fast‑down switch and recheck the DTC to see if code changes
- Backprobe the switch connector with ignition on and measure voltage on the fast‑down signal
- Inspect for aftermarket wiring or recent bodywork in the door area
Signal parameters
- Ignition ON, battery voltage at power feed: ~11–14 V
- Expected fast‑down input (rest): open or pulled to reference (varies by design) — typically 0 V or a low signal when not activated
- Fast‑down when pressed: should change state (either switch to ground ≈0 V or to battery voltage ≈11–14 V depending on design)
- Short condition: fast‑down input reads constant battery voltage (~11–14 V) when it should not
- Switch closed resistance: near 0 Ω between intended terminals; open should be >>10 kΩ
Diagnostic algorithm
- Verify the code and note if it’s current or historic. Record any related codes.
- With ignition ON (engine off), visually inspect the door wiring harness at the A‑pillar/hinge and the switch connector for damage, corrosion or pin contact with power wires.
- Remove the door switch trim and disconnect the fast‑down switch. Clear the code, then operate the window switches to see if code returns.
- With the switch disconnected, backprobe the fast‑down input at the harness connector. Measure voltage to ground with key ON: if you read battery voltage with the switch open, there is a short to positive in the harness or module.
- If the harness shows battery voltage at the input, physically trace the wire toward the body control module and the door harness. Look for chafing at the hinge and repair any damaged sections (splice, replace section, or replace harness as required).
- If the harness input is not at battery voltage with switch disconnected, test the switch on the bench for internal short (measure resistance between terminals, operate switch). Replace switch if faulty.
- If wiring and switch check good, use a scan tool to monitor the BCM input while operating other window/door functions; suspect BCM if input behaves incorrectly and wiring/switch are confirmed good.
- After repair/replacement, clear codes and verify proper auto‑down operation and that B1243 does not return. Perform a road/test cycles of window operation to confirm.
Likely causes
- Pin or conductor contacting +12V wiring in door harness (wear at hinge area)
- Switch terminal contaminated with battery voltage (corrosion/debris)
- Connector mis‑mated after service or replaced with incorrect part
- Short inside the switch assembly (internal insulation failure)
- Power feed wire routed too close to a fused ignition/battery circuit and chafed through
Fault status
Status
Fast window descent switch circuit shorted to positive (B1243) — high voltage detected on fast‑down input.
Repair difficulty: Medium
Diagnostic time: 0.5-1.5 hours
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Code
B1243
FIAT
B — Body
Fast window descent switch short to positive
Views:
UK: 3
EN: 8
RU: 2
AI status
Completed
Completed
100%
Causes
- Shorted switch wiring to battery positive
- Damaged or chafed harness contacting a power feed
- Faulty fast descent (auto down) switch with internal short
- Corroded or contaminated connector causing unintended positive feed
- Failed body control module (BCM) input or internal hardware fault
- Aftermarket accessories or recent repairs that disturbed wiring
Symptoms
- Auto (one‑touch) window down function not working
- Intermittent or permanent inability to lower the affected window automatically
- Possible illumination of a related body/control warning or message
- Window may still operate in manual/hold mode if allowed by design
- DTC B1243 stored and can be retrieved by diagnostic tool
What to check
- Confirm code with a suitable diagnostic scanner and record freeze frame/live data
- Visual inspection of door harness at hinge, connectors and switch for damage, corrosion or pin pushed out
- Check related fuses and relays for the power windows circuit
- Disconnect the fast‑down switch and recheck the DTC to see if code changes
- Backprobe the switch connector with ignition on and measure voltage on the fast‑down signal
- Inspect for aftermarket wiring or recent bodywork in the door area
Signal parameters
- Ignition ON, battery voltage at power feed: ~11–14 V
- Expected fast‑down input (rest): open or pulled to reference (varies by design) — typically 0 V or a low signal when not activated
- Fast‑down when pressed: should change state (either switch to ground ≈0 V or to battery voltage ≈11–14 V depending on design)
- Short condition: fast‑down input reads constant battery voltage (~11–14 V) when it should not
- Switch closed resistance: near 0 Ω between intended terminals; open should be >>10 kΩ
Diagnostic algorithm
- Verify the code and note if it’s current or historic. Record any related codes.
- With ignition ON (engine off), visually inspect the door wiring harness at the A‑pillar/hinge and the switch connector for damage, corrosion or pin contact with power wires.
- Remove the door switch trim and disconnect the fast‑down switch. Clear the code, then operate the window switches to see if code returns.
- With the switch disconnected, backprobe the fast‑down input at the harness connector. Measure voltage to ground with key ON: if you read battery voltage with the switch open, there is a short to positive in the harness or module.
- If the harness shows battery voltage at the input, physically trace the wire toward the body control module and the door harness. Look for chafing at the hinge and repair any damaged sections (splice, replace section, or replace harness as required).
- If the harness input is not at battery voltage with switch disconnected, test the switch on the bench for internal short (measure resistance between terminals, operate switch). Replace switch if faulty.
- If wiring and switch check good, use a scan tool to monitor the BCM input while operating other window/door functions; suspect BCM if input behaves incorrectly and wiring/switch are confirmed good.
- After repair/replacement, clear codes and verify proper auto‑down operation and that B1243 does not return. Perform a road/test cycles of window operation to confirm.
Likely causes
- Pin or conductor contacting +12V wiring in door harness (wear at hinge area)
- Switch terminal contaminated with battery voltage (corrosion/debris)
- Connector mis‑mated after service or replaced with incorrect part
- Short inside the switch assembly (internal insulation failure)
- Power feed wire routed too close to a fused ignition/battery circuit and chafed through
Fault status
Status
Fast window descent switch circuit shorted to positive (B1243) — high voltage detected on fast‑down input.
Repair difficulty: Medium
Diagnostic time: 0.5-1.5 hours
Similar codes
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Code
B1243
LAND ROVER
B — Body
Winter Mode indicator dynamic button
Views:
UK: 4
EN: 8
RU: 3
AI status
Completed
Completed
100%
Causes
- Shorted switch wiring to battery positive
- Damaged or chafed harness contacting a power feed
- Faulty fast descent (auto down) switch with internal short
- Corroded or contaminated connector causing unintended positive feed
- Failed body control module (BCM) input or internal hardware fault
- Aftermarket accessories or recent repairs that disturbed wiring
Symptoms
- Auto (one‑touch) window down function not working
- Intermittent or permanent inability to lower the affected window automatically
- Possible illumination of a related body/control warning or message
- Window may still operate in manual/hold mode if allowed by design
- DTC B1243 stored and can be retrieved by diagnostic tool
What to check
- Confirm code with a suitable diagnostic scanner and record freeze frame/live data
- Visual inspection of door harness at hinge, connectors and switch for damage, corrosion or pin pushed out
- Check related fuses and relays for the power windows circuit
- Disconnect the fast‑down switch and recheck the DTC to see if code changes
- Backprobe the switch connector with ignition on and measure voltage on the fast‑down signal
- Inspect for aftermarket wiring or recent bodywork in the door area
Signal parameters
- Ignition ON, battery voltage at power feed: ~11–14 V
- Expected fast‑down input (rest): open or pulled to reference (varies by design) — typically 0 V or a low signal when not activated
- Fast‑down when pressed: should change state (either switch to ground ≈0 V or to battery voltage ≈11–14 V depending on design)
- Short condition: fast‑down input reads constant battery voltage (~11–14 V) when it should not
- Switch closed resistance: near 0 Ω between intended terminals; open should be >>10 kΩ
Diagnostic algorithm
- Verify the code and note if it’s current or historic. Record any related codes.
- With ignition ON (engine off), visually inspect the door wiring harness at the A‑pillar/hinge and the switch connector for damage, corrosion or pin contact with power wires.
- Remove the door switch trim and disconnect the fast‑down switch. Clear the code, then operate the window switches to see if code returns.
- With the switch disconnected, backprobe the fast‑down input at the harness connector. Measure voltage to ground with key ON: if you read battery voltage with the switch open, there is a short to positive in the harness or module.
- If the harness shows battery voltage at the input, physically trace the wire toward the body control module and the door harness. Look for chafing at the hinge and repair any damaged sections (splice, replace section, or replace harness as required).
- If the harness input is not at battery voltage with switch disconnected, test the switch on the bench for internal short (measure resistance between terminals, operate switch). Replace switch if faulty.
- If wiring and switch check good, use a scan tool to monitor the BCM input while operating other window/door functions; suspect BCM if input behaves incorrectly and wiring/switch are confirmed good.
- After repair/replacement, clear codes and verify proper auto‑down operation and that B1243 does not return. Perform a road/test cycles of window operation to confirm.
Likely causes
- Pin or conductor contacting +12V wiring in door harness (wear at hinge area)
- Switch terminal contaminated with battery voltage (corrosion/debris)
- Connector mis‑mated after service or replaced with incorrect part
- Short inside the switch assembly (internal insulation failure)
- Power feed wire routed too close to a fused ignition/battery circuit and chafed through
Fault status
Status
Fast window descent switch circuit shorted to positive (B1243) — high voltage detected on fast‑down input.
Repair difficulty: Medium
Diagnostic time: 0.5-1.5 hours
Similar codes
Workshop Manuals
Repair manuals for LAND ROVER
3
Land Rover Defender 300Tdi — Workshop Manual (1996 model year)
Workshop ManualLand Rover Defender Workshop Manual Supplement & Body Repair Manual (1999 & 2002 MY)
Workshop ManualLand Rover Range Rover — Electrical Library (LRL 0453ENG, 2002)
Workshop ManualYour experience will help others
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Code
B1243
Other
B — Body
Express Window Down Switch Circuit Short to Battery
Views:
UK: 15
EN: 22
RU: 17
AI status
Completed
Completed
100%
Causes
- Shorted switch wiring to battery positive
- Damaged or chafed harness contacting a power feed
- Faulty fast descent (auto down) switch with internal short
- Corroded or contaminated connector causing unintended positive feed
- Failed body control module (BCM) input or internal hardware fault
- Aftermarket accessories or recent repairs that disturbed wiring
Symptoms
- Auto (one‑touch) window down function not working
- Intermittent or permanent inability to lower the affected window automatically
- Possible illumination of a related body/control warning or message
- Window may still operate in manual/hold mode if allowed by design
- DTC B1243 stored and can be retrieved by diagnostic tool
What to check
- Confirm code with a suitable diagnostic scanner and record freeze frame/live data
- Visual inspection of door harness at hinge, connectors and switch for damage, corrosion or pin pushed out
- Check related fuses and relays for the power windows circuit
- Disconnect the fast‑down switch and recheck the DTC to see if code changes
- Backprobe the switch connector with ignition on and measure voltage on the fast‑down signal
- Inspect for aftermarket wiring or recent bodywork in the door area
Signal parameters
- Ignition ON, battery voltage at power feed: ~11–14 V
- Expected fast‑down input (rest): open or pulled to reference (varies by design) — typically 0 V or a low signal when not activated
- Fast‑down when pressed: should change state (either switch to ground ≈0 V or to battery voltage ≈11–14 V depending on design)
- Short condition: fast‑down input reads constant battery voltage (~11–14 V) when it should not
- Switch closed resistance: near 0 Ω between intended terminals; open should be >>10 kΩ
Diagnostic algorithm
- Verify the code and note if it’s current or historic. Record any related codes.
- With ignition ON (engine off), visually inspect the door wiring harness at the A‑pillar/hinge and the switch connector for damage, corrosion or pin contact with power wires.
- Remove the door switch trim and disconnect the fast‑down switch. Clear the code, then operate the window switches to see if code returns.
- With the switch disconnected, backprobe the fast‑down input at the harness connector. Measure voltage to ground with key ON: if you read battery voltage with the switch open, there is a short to positive in the harness or module.
- If the harness shows battery voltage at the input, physically trace the wire toward the body control module and the door harness. Look for chafing at the hinge and repair any damaged sections (splice, replace section, or replace harness as required).
- If the harness input is not at battery voltage with switch disconnected, test the switch on the bench for internal short (measure resistance between terminals, operate switch). Replace switch if faulty.
- If wiring and switch check good, use a scan tool to monitor the BCM input while operating other window/door functions; suspect BCM if input behaves incorrectly and wiring/switch are confirmed good.
- After repair/replacement, clear codes and verify proper auto‑down operation and that B1243 does not return. Perform a road/test cycles of window operation to confirm.
Likely causes
- Pin or conductor contacting +12V wiring in door harness (wear at hinge area)
- Switch terminal contaminated with battery voltage (corrosion/debris)
- Connector mis‑mated after service or replaced with incorrect part
- Short inside the switch assembly (internal insulation failure)
- Power feed wire routed too close to a fused ignition/battery circuit and chafed through
Fault status
Status
Fast window descent switch circuit shorted to positive (B1243) — high voltage detected on fast‑down input.
Repair difficulty: Medium
Diagnostic time: 0.5-1.5 hours
Similar codes
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Workshop ManualYour experience will help others
+100 karma for a short comment :)
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