Code
B1652
HUMMER
B — Body
Loss of Keep Alive Memory (KAM)
Views:
UK: 1
EN: 12
RU: 8
AI status
Completed
Completed
100%
Causes
- Battery disconnected or recently replaced without proper procedure
- Low battery voltage or repeated deep discharges
- Loose, corroded or damaged battery terminals or ground connections
- Blown fuse or open circuit on the KAM supply or ground
- Faulty body control module (BCM) or other module that maintains KAM
- Wiring harness damage or connector issues on the KAM power/ground circuits
Symptoms
- Loss of radio presets, clock, seat/mirror memory or other personalized settings
- Security/immobilizer warnings or unexpected behavior
- Stored convenience feature settings reset to defaults
- Possible multiple related DTCs or communication errors after power interruption
- No obvious drivability symptoms in many cases (but module functions may be affected)
What to check
- Check battery state of charge and cranking/resting voltage
- Inspect battery terminals, cable ends and chassis grounds for tightness and corrosion
- Verify relevant fuses (body/retention/KAM feed) are intact
- Scan for additional DTCs and any module communication errors (U-codes)
- Check service history for recent battery disconnection, module replacement or reflash
- Measure KAM supply and ground at the BCM connector with key off (see diagnostic steps)
Signal parameters
- KAM supply voltage: nominal battery voltage (~12.6 V rested); should remain present with ignition off
- Retention current: typically very low (microamp to low milliamp range) with ignition off
- Voltage threshold: memory may be lost if battery falls well below normal (varies by module, often < 9–10 V)
- No pulses or intermittent voltage on KAM feed when vehicle is parked and key off
- Related CAN/serial messages present and stable when ignition on
Diagnostic algorithm
- Retrieve freeze frame and scan all modules; note any related DTCs (U-codes or other B-codes).
- Ask customer about recent battery service or accessories installed. If battery was disconnected, confirm proper procedure used.
- Check battery resting voltage. If low, charge or replace battery and clear code. Recheck after normal service voltage is restored.
- Visually inspect and clean battery terminals, cable ends and primary grounds. Tighten to spec and recheck.
- Verify fuses for the BCM/KAM supply. Replace any blown fuses and re-check for memory loss.
- With ignition off, backprobe the KAM power/retain pin at the BCM (refer to vehicle wiring diagram) and verify a steady battery voltage is present. Check for excessive current draw if voltage drops.
- Wiggle test harnesses and connectors at BCM while monitoring KAM supply for intermittent opens/shorts.
- Perform a parasitic draw test if memory loss is intermittent to identify aftermarket loads or faults.
- If wiring and power are good, check for software updates and re-flash/repair BCM per factory service instructions.
- If module fails to retain memory after verified good power and updated software, consider BCM replacement and follow immobilizer/programming procedures as required.
- After repairs, clear codes, verify retained settings after a key cycle and road test as needed.
Likely causes
- Battery was disconnected during service or replacement
- Battery voltage dropped below retention threshold (e.g., during cranking or due to a weak battery)
- Poor battery/ground connections causing intermittent KAM supply
- Blown fuse for memory/retain circuit
- Internal BCM fault or failed non-volatile memory
Fault status
Status
Loss of Keep Alive Memory detected — module reports KAM cleared or not retained. May occur after battery disconnect, low voltage, or module/wiring fault. Investigate battery, fuses, connections, and BCM.
Repair difficulty: Medium
Diagnostic time: 0.5 - 2.0 hours
Similar codes
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Code
B1652
Other
B — Body
Seat Driver Recline Backward Circuit Open
Views:
UK: 11
EN: 26
RU: 21
AI status
Completed
Completed
100%
Causes
- Battery disconnected or recently replaced without proper procedure
- Low battery voltage or repeated deep discharges
- Loose, corroded or damaged battery terminals or ground connections
- Blown fuse or open circuit on the KAM supply or ground
- Faulty body control module (BCM) or other module that maintains KAM
- Wiring harness damage or connector issues on the KAM power/ground circuits
Symptoms
- Loss of radio presets, clock, seat/mirror memory or other personalized settings
- Security/immobilizer warnings or unexpected behavior
- Stored convenience feature settings reset to defaults
- Possible multiple related DTCs or communication errors after power interruption
- No obvious drivability symptoms in many cases (but module functions may be affected)
What to check
- Check battery state of charge and cranking/resting voltage
- Inspect battery terminals, cable ends and chassis grounds for tightness and corrosion
- Verify relevant fuses (body/retention/KAM feed) are intact
- Scan for additional DTCs and any module communication errors (U-codes)
- Check service history for recent battery disconnection, module replacement or reflash
- Measure KAM supply and ground at the BCM connector with key off (see diagnostic steps)
Signal parameters
- KAM supply voltage: nominal battery voltage (~12.6 V rested); should remain present with ignition off
- Retention current: typically very low (microamp to low milliamp range) with ignition off
- Voltage threshold: memory may be lost if battery falls well below normal (varies by module, often < 9–10 V)
- No pulses or intermittent voltage on KAM feed when vehicle is parked and key off
- Related CAN/serial messages present and stable when ignition on
Diagnostic algorithm
- Retrieve freeze frame and scan all modules; note any related DTCs (U-codes or other B-codes).
- Ask customer about recent battery service or accessories installed. If battery was disconnected, confirm proper procedure used.
- Check battery resting voltage. If low, charge or replace battery and clear code. Recheck after normal service voltage is restored.
- Visually inspect and clean battery terminals, cable ends and primary grounds. Tighten to spec and recheck.
- Verify fuses for the BCM/KAM supply. Replace any blown fuses and re-check for memory loss.
- With ignition off, backprobe the KAM power/retain pin at the BCM (refer to vehicle wiring diagram) and verify a steady battery voltage is present. Check for excessive current draw if voltage drops.
- Wiggle test harnesses and connectors at BCM while monitoring KAM supply for intermittent opens/shorts.
- Perform a parasitic draw test if memory loss is intermittent to identify aftermarket loads or faults.
- If wiring and power are good, check for software updates and re-flash/repair BCM per factory service instructions.
- If module fails to retain memory after verified good power and updated software, consider BCM replacement and follow immobilizer/programming procedures as required.
- After repairs, clear codes, verify retained settings after a key cycle and road test as needed.
Likely causes
- Battery was disconnected during service or replacement
- Battery voltage dropped below retention threshold (e.g., during cranking or due to a weak battery)
- Poor battery/ground connections causing intermittent KAM supply
- Blown fuse for memory/retain circuit
- Internal BCM fault or failed non-volatile memory
Fault status
Status
Loss of Keep Alive Memory detected — module reports KAM cleared or not retained. May occur after battery disconnect, low voltage, or module/wiring fault. Investigate battery, fuses, connections, and BCM.
Repair difficulty: Medium
Diagnostic time: 0.5 - 2.0 hours
Similar codes
Workshop Manuals
Available brands with manuals
1
LAND ROVER 1
Land Rover Defender Workshop Manual Supplement & Body Repair Manual (1999 & 2002 MY)
Workshop ManualWorkshop Manual Supplement and Body Repair Manual for the Land Rover Defender. Includes general specifications, maintenance schedules, tuning data and step‑by‑step repair procedures for engine, transmission, suspension, brakes, electrical and body repairs. Covers Defender models from 1999 and 2002 model years.
Key sections:
Buy - 01 - INTRODUCTION
- - Introduction
- - Dimensions
- - References
- - Repairs and replacements
- - Poisonous substances
- - Fuel handling precautions
- - Synthetic rubber
- - Recommended sealants
- - Used engine oil precautions
- - Accessories and conversions
- - Wheels and tyres
Your experience will help others
+100 karma for a short comment :)
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