OBD-II code · Network (extended)
U3506 Control Module Input Power B Circuit High
Input power line B voltage above expected range. A communication loss with this module breaks any function relying on its data — diagnostic tools may show 'no response' and dependent modules can fall into limp mode.
Is it safe to drive with U3506?
The car may go into limp mode (reduced power). Get it diagnosed before a long trip.
Common causes
- Most likelyAlternator regulator failed
- Less likelyGateway module routing CAN messages incorrectly
- Less likelyCAN terminating resistor (120 Ω) drifted out of spec
Symptoms
- Multiple warning lights may illuminate
- Affected modules may go into limp mode or shut down
- Specific functions inoperative depending on module
- Diagnostic tools may show communication faults
Repair at a glance
- Difficulty
- Medium
- DIY friendly
- Often, with basic tools
- Typical labour
- 0.5–3 h
- Emissions test
- Usually unaffected
- Parts involved
- Module Power B, Charging System
Related codes
- U3502Control Module Input Power A Circuit High
- U350AControl Module Input Power C Circuit High
- U3503Control Module Input Power A Circuit Intermittent/Erratic
- U3504Control Module Input Power B Circuit Range/Performance
- U3505Control Module Input Power B Circuit Low
- U3507Control Module Input Power B Circuit Intermittent/Erratic
- U3508Control Module Input Power C Circuit Range/Performance
- U3509Control Module Input Power C Circuit Low
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.