U3507

Code

Generic U — Network/User

Control Module Input Power B Circuit Intermittent/Erratic

Brand: Generic

Type: U — Network/User

Views: UK: 19 EN: 27 RU: 23

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Loose, corroded or damaged battery/ignition power connection to the module
Blown or partially open fuse or fusible link on Power B circuit
Damaged, chafed or shorted wiring harness (open, short to ground or short to battery)
Poor or intermittent chassis or engine ground(s) affecting module reference
Intermittent ignition switch or relay connection feeding the Power B circuit
Water intrusion, corrosion or contaminated connector pins at the module

Stored and/or intermittent U3507 fault present; may clear and return
Intermittent loss of functions controlled by that module (lighting, instrument cluster, communication, driveability features depending on module)
Unexpected resets or reboots of the affected control module
Multiple network communication errors or other U-codes present
Vehicle may start/operate normally at times and fail or show faults at other times

Read and record freeze frame, occurrence count and related U-codes with a capable scan tool
Visually inspect battery terminals, main power feeds, fuses and fusible links for corrosion, looseness or heat damage
Inspect module connector(s) for corrosion, bent pins, water entry or loose terminals
Measure battery voltage with key off and key on; check voltage under cranking and under load
Check integrity of module ground(s; clean and torque to spec)
Perform wiggle/strain test of wiring harness while monitoring voltage or live data to reproduce fault

Nominal supply expected: ~12–14.5 V with ignition ON; stable within ±0.5 V
Intermittent drops below ~9–10 V or rapid voltage sag during load are indicative of a fault
Spikes above normal charging voltage (>15.5–16 V) or high-frequency noise may indicate charging system or regulator issues
Open circuit: near 0 V at module power pin with key ON; short to battery: constant battery voltage regardless of ignition state
High series resistance: measured voltage lower at module than battery by >0.5–1.0 V under load

Connect a scan tool and record current and pending U-codes, freeze frame data and event counters
Visually inspect battery, main power distribution, fuses, fusible links and relay related to Power B circuit
With key ON, backprobe the module Power B input pin and measure voltage at rest and while cycling ignition; compare to battery voltage
Check continuity and resistance between module power pin and the fuse/battery feed; repair any high resistance or open readings
Inspect and clean module connectors; look for corrosion, bent pins, and secure latch engagement. Repair or replace connector as required
Check module ground(s): disconnect, inspect, clean mating surfaces and verify low resistance (
Perform wiggle test on wiring harness and connectors while monitoring voltage/live data to reproduce intermittent behavior
If harness and connectors are good, check upstream components: ignition switch, relays, charging system for abnormal voltage or noise
If wiring/power/ground and external components check good, check for available software updates and reprogram the module per manufacturer procedure
If fault persists after wiring, connectors and software verified, consider module repair or replacement and follow proper programming and configuration steps
After repairs, clear codes and perform a road test under conditions that previously produced the fault; re-scan and confirm issue resolved

Loose or corroded connector pin at the module or fusebox
Bad ground on the module or nearby grounding strap
Partially open fuse or high resistance in fusible link
Wiring damage in harness near wheel wells, doors, or engine bay where movement occurs
Faulty ignition switch or relay feeding the circuit