B0600

Code

Generic B — Body

Body Control Module Internal Circuit Malfunction

Brand: Generic

Type: B — Body

Views: UK: 16 EN: 26 RU: 16

AI status

Completed

ready

Completed 100%

Page language: EN

Causes

Intermittent or low battery/vehicle supply voltage
Corroded/damaged BCM connector or wiring short/open
Blown fuse or failed relay supplying BCM
Water/contamination or physical damage to BCM
BCM software corruption or failed firmware
Internal BCM hardware failure

Symptoms

Multiple body systems inoperative or intermittent (lighting, locks, wipers, windows, HVAC blower, etc.)
Illumination of general warning lamp or BCM-specific warning
Loss of communication with BCM on diagnostic tool (CAN/LIN errors)
Erratic or unexplained behavior of body functions
Possible parasitic battery drain

What to check

Read and record freeze frame and full DTC list with a scan tool; note if other U- or B-codes are present
Verify battery state of charge and test charging system (voltage stable 12.4–14.6 V at key ON/engine running)
Inspect BCM area for water intrusion, corrosion, or physical damage
Inspect BCM connectors and harness for damaged wires, pushed-out pins, corrosion, or improper repairs
Check fuses and relays that supply BCM power and ground circuits
Check vehicle grounds and measure voltage drop on ground circuit

Signal parameters

BCM supply voltage (key ON): ~11–15 V (manufacturer specific; verify spec)
Battery voltage at rest: typically 12.2–12.8 V (healthy battery >12.4 V preferred for testing)
Ground voltage drop:
CAN high/low differential idle: ~2.5 V each side (~0 V differential) or ~2.5 V/1.5–3.5 V depending on network (verify vehicle spec)
LIN bus idle: near Vbatt or low (manufacturer specific), check for valid wake messages
BCM wake/sleep behavior: expected wake signal when key or door switch activated; check timing against spec

Diagnostic algorithm

Capture and record all codes, freeze frame, and symptoms; check for accompanying U-codes that indicate network loss.
Verify battery charge and charging system; recharge or install a known-good battery if voltage is low and retest.
Perform a visual inspection of BCM and harness for contamination, water entry, heat damage, or rodent damage.
Inspect and wiggle BCM connectors with ignition ON while watching live data/communication; look for intermittent contact or fault appearance.
Check and test all fuses/relays feeding the BCM; replace suspect items and retest.
Measure supply and ground at the BCM with a digital multimeter; check for excessive voltage drop during activation of loads.
Monitor CAN/LIN communication with a scan tool or scope; verify message traffic and proper bus voltages.
If connectors, power, and network are good, attempt a soft reset/relearn per manufacturer procedure (clear codes and cycle ignition); see if code returns.
Check for and apply any BCM software updates or reflash as directed by manufacturer; follow programming and immobilizer security procedures when replacing or reprogramming.
If internal BCM fault persists after verifying vehicle wiring and communications, follow OEM procedure for module replacement and programming. Retest vehicle functions and clear codes.
Safety note: follow battery disconnect and airbag/body module handling procedures from the manufacturer when removing or replacing modules.

Likely causes

Battery voltage below normal (cranking/weak battery) during BCM operation
Poor ground at BCM chassis/engine ground stud
Bent/oxidized pins in the BCM connector causing intermittent contact
Electrical overstress from jump-start, battery disconnect, or incorrect battery connection
Failed internal microcontroller or memory corruption
Aftermarket accessory or incorrect wiring interfering with BCM power/communication

Fault status

⚠️ Status

BCM detected an internal circuit malfunction — internal electronics, memory, or communications within the Body Control Module are not operating correctly.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 0.5-3.0 hours