Code
B1728
MITSUBISHI
B — Body
Supply voltage(undervoltage)
Views:
UK: 6
EN: 8
RU: 8
AI status
Completed
Completed
100%
Causes
- Weak or discharged battery
- Poor battery negative or positive terminal connection (corrosion, loose)
- Blown fuse or fusible link on the module supply circuit
- Faulty alternator or charging system (no or low charge)
- Damaged wiring, chafed harness or connector corrosion on the supply or ground circuits
- High-resistance ground(s) at chassis or engine block
Symptoms
- Malfunction indicator lamps or warning messages related to systems controlled by the module
- Intermittent or permanent loss of functions controlled by the affected module
- Difficulty starting or cranking with low battery voltage
- Erratic module behavior, resets, or communication errors on scan tool
- Additional DTCs related to low system voltage or communications
What to check
- Visually inspect battery terminals and cables for corrosion, damage, or loose connections
- Measure battery resting voltage (key off) — normally ~12.4–12.8 V for a charged battery
- Perform cranking voltage check (during starter engagement) — should normally stay above ~9.5 V
- Start engine and measure charging voltage at battery — should be ~13.5–14.8 V
- Inspect and test fuses/fusible links and fuse holders for continuity and high resistance
- Inspect harness and connector at the affected module for corrosion, bent pins, water ingress or damage
Signal parameters
- Nominal battery (rest): ~12.4–12.8 V (fully charged ~12.6 V)
- Cranking voltage expected: typically >9.5 V during starter engagement
- Charging system (running) voltage: 13.5–14.8 V
- Undervoltage detection threshold (typical): module may flag undervoltage below ~9–10 V or when voltage dips persistently below expected operating range
- Transient dips under heavy load may be allowed briefly; repeated/prolonged low values are problematic
Diagnostic algorithm
- Read freeze frame/confirm when code set (key on, cranking, running) and note related codes. Do not clear immediately. 2) Visually inspect battery, terminals, cables, and ground straps. Clean and tighten as required. 3) Measure battery resting voltage. If below ~12.2 V, charge battery fully and perform load/crank tests. 4) With a DVOM, measure voltage at battery positive and negative during cranking and with engine running; record values. 5) Inspect and test the alternator/charging system output; verify regulator function and belt condition. 6) Check continuity and resistance of fusible links, fuses and their holders supplying the module; replace if high resistance or open. 7) Probe the module supply pin(s) at the module connector with ignition ON and during cranking/running; compare to battery voltage to locate voltage drop points. 8) Wiggle test harness and connectors while monitoring voltage to detect intermittent connections. 9) Inspect chassis/engine grounds and repair/clean connections; measure ground resistance to battery negative. 10) If wiring and power/ground are good and voltage at the module is within expected range but the code persists, consider module internal fault — consult manufacturer data and consider replacement or bench testing. 11) After repairs, clear codes, verify system operation, and perform a road test to confirm code does not return.
Likely causes
- Battery state of charge low or battery near end of life
- Loose/corroded battery terminals or poor ground strap connection
- Fusible link/fuse supplying the module opened or high resistance in fuse holder
- Open/shorted wiring between battery/ignition and the module harness connector
- Alternator failing to maintain charge at idle or under load
Fault status
Status
Module detected supply voltage below acceptable threshold (undervoltage) on its power input.
Repair difficulty: Medium
Diagnostic time: 0.5-2.0 hours
Similar codes
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
Code
B1728
Other
B — Body
Seat Driver Rear Up Switch Circuit Short To Ground
Views:
UK: 15
EN: 19
RU: 15
AI status
Completed
Completed
100%
Causes
- Weak or discharged battery
- Poor battery negative or positive terminal connection (corrosion, loose)
- Blown fuse or fusible link on the module supply circuit
- Faulty alternator or charging system (no or low charge)
- Damaged wiring, chafed harness or connector corrosion on the supply or ground circuits
- High-resistance ground(s) at chassis or engine block
Symptoms
- Malfunction indicator lamps or warning messages related to systems controlled by the module
- Intermittent or permanent loss of functions controlled by the affected module
- Difficulty starting or cranking with low battery voltage
- Erratic module behavior, resets, or communication errors on scan tool
- Additional DTCs related to low system voltage or communications
What to check
- Visually inspect battery terminals and cables for corrosion, damage, or loose connections
- Measure battery resting voltage (key off) — normally ~12.4–12.8 V for a charged battery
- Perform cranking voltage check (during starter engagement) — should normally stay above ~9.5 V
- Start engine and measure charging voltage at battery — should be ~13.5–14.8 V
- Inspect and test fuses/fusible links and fuse holders for continuity and high resistance
- Inspect harness and connector at the affected module for corrosion, bent pins, water ingress or damage
Signal parameters
- Nominal battery (rest): ~12.4–12.8 V (fully charged ~12.6 V)
- Cranking voltage expected: typically >9.5 V during starter engagement
- Charging system (running) voltage: 13.5–14.8 V
- Undervoltage detection threshold (typical): module may flag undervoltage below ~9–10 V or when voltage dips persistently below expected operating range
- Transient dips under heavy load may be allowed briefly; repeated/prolonged low values are problematic
Diagnostic algorithm
- Read freeze frame/confirm when code set (key on, cranking, running) and note related codes. Do not clear immediately. 2) Visually inspect battery, terminals, cables, and ground straps. Clean and tighten as required. 3) Measure battery resting voltage. If below ~12.2 V, charge battery fully and perform load/crank tests. 4) With a DVOM, measure voltage at battery positive and negative during cranking and with engine running; record values. 5) Inspect and test the alternator/charging system output; verify regulator function and belt condition. 6) Check continuity and resistance of fusible links, fuses and their holders supplying the module; replace if high resistance or open. 7) Probe the module supply pin(s) at the module connector with ignition ON and during cranking/running; compare to battery voltage to locate voltage drop points. 8) Wiggle test harness and connectors while monitoring voltage to detect intermittent connections. 9) Inspect chassis/engine grounds and repair/clean connections; measure ground resistance to battery negative. 10) If wiring and power/ground are good and voltage at the module is within expected range but the code persists, consider module internal fault — consult manufacturer data and consider replacement or bench testing. 11) After repairs, clear codes, verify system operation, and perform a road test to confirm code does not return.
Likely causes
- Battery state of charge low or battery near end of life
- Loose/corroded battery terminals or poor ground strap connection
- Fusible link/fuse supplying the module opened or high resistance in fuse holder
- Open/shorted wiring between battery/ignition and the module harness connector
- Alternator failing to maintain charge at idle or under load
Fault status
Status
Module detected supply voltage below acceptable threshold (undervoltage) on its power input.
Repair difficulty: Medium
Diagnostic time: 0.5-2.0 hours
Similar codes
Workshop Manuals
Available brands with manuals
2
AUDI 11
6-speed manual gearbox 0B1, front-wheel drive — Workshop Manual (Edition 05.2014)
Workshop Manual199,00 UAH
Audi A3 (1997) – 1.6L 4-cylinder (2‑valve) Engine Mechanical Components Service Manual (AEH, AKL, APF) – Edition 07.2002
Workshop Manual199,00 UAH
AUDI A3 (2004) Workshop Manual — 2.0L FSI Turbo (4‑cyl, 4‑valve) Engine, Mechanics — Edition 03.2017
Workshop Manual199,00 UAH
Audi A3 2004 — Electrical System (Workshop Manual, Edition 02.2018)
Workshop Manual199,00 UAH
Audi A4 / A4 Cabriolet – 4.2 l V8 (5‑valve, timing chains) – Workshop Manual (Mechanics) – Edition 04.2007
Workshop Manual199,00 UAH
Audi A4 / A4 Cabriolet — Auxiliary Heater Workshop Manual (Edition 08.2004)
Workshop Manual199,00 UAH
Audi A4 / A4 Cabriolet (1.8T 4‑cyl turbo) — Motronic Injection & Ignition System Service Manual (Edition 01.2015)
Workshop Manual199,00 UAH
Audi A8 (2003) — Electrical System Workshop Manual (Edition 08.2014)
Workshop Manual199,00 UAH
Audi Q4 e-tron (Type F4) - Self-study Programme SSP 685
Workshop Manual199,00 UAH
Audi Q8 (2018) — Electrical System Workshop Manual (Edition 05.2019)
Workshop Manual199,00 UAH
Audi Servicing Manual — 7‑Speed Dual Clutch Transmission 0CJ / 0CL / 0CK / 0DN / 0DP / 0HL (Edition 05.2018)
Workshop Manual199,00 UAH
LAND ROVER 3
Land Rover Defender 300Tdi — Workshop Manual (1996 model year)
Workshop Manual199,00 UAH
Land Rover Defender Workshop Manual Supplement & Body Repair Manual (1999 & 2002 MY)
Workshop Manual199,00 UAH
Land Rover Range Rover — Electrical Library (LRL 0453ENG, 2002)
Workshop Manual199,00 UAH
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