What Does U3007 Mean?
DTC U3007 indicates that a control module has detected a fault on its secondary power input circuit, designated as power input 'B.' This is the companion code to U3006 (power input 'A'). The 'B' power feed often provides either keep-alive (constant battery) power or a second switched ignition power source. When this circuit fails, the module may lose its stored memory, fail to wake up, or lose a subset of its functions.
Common Causes
35%
Open or high-resistance connection in the power input 'B' feed wire — corroded pin, damaged wire, or failed splice in the secondary power circuit
30%
Blown fuse in the power input 'B' circuit — this may be a different fuse from the 'A' circuit, often a keep-alive or battery-direct fuse
20%
Faulty power distribution relay or junction block terminal feeding the 'B' power circuit
15%
Internal module failure on the 'B' power input regulator or protection circuit
Diagnostic Steps
1
Step 1: Identify the affected control module and locate the power input 'B' pin using the vehicle wiring diagram — determine if this is a battery-direct (constant) or switched power feed.
2
Step 2: Measure voltage at the module's power input 'B' pin — if it's a battery-direct feed, it should read 12.4-12.7V with ignition off and 13.8-14.5V with engine running; if switched, verify it has voltage in the correct ignition positions.
3
Step 3: Trace the circuit to its fuse and verify fuse integrity — check for voltage on both sides of the fuse and inspect for burnt or loose fuse blade contacts.
4
Step 4: Perform a wiggle test on the wiring harness from the fuse box to the module connector while monitoring voltage at the module pin — an intermittent connection will cause voltage to drop momentarily.
5
Step 5: If all wiring checks pass, compare the module's reported voltage on the scan tool with the actual measured voltage at the pin — a significant discrepancy indicates an internal module sensing fault requiring module replacement.
Estimated Repair Cost
$50 - $500
Parts + labor, varies by vehicle and location
DTC U3007 indicates that a control module has detected a fault on its secondary power input circuit, designated as power input 'B.' This is the companion code to U3006 (power input 'A'). The 'B' power feed often provides either keep-alive (constant battery) power or a second switched ignition power ...
The most common cause of U3007 (Control Module Input Power "B") is: Open or high-resistance connection in the power input 'B' feed wire — corroded pin, damaged wire, or failed splice in the secondary power circuit
Typical repair costs for U3007 range from $50 to $500, depending on the vehicle, location, and whether you do it yourself or go to a shop.
If the 'B' power feed is the keep-alive circuit, the module will lose all stored data on each power cycle, causing driveability issues and repeated adaptation relearns. If it is a secondary switched feed, certain module functions may be disabled. Diagnose before extended driving.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to U3007 to identify the root cause.
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Quick Info
Category
Network
System
Control Module Power Supply Circuit
Difficulty
Type
Generic (SAE)
Recommended Tools
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