What Does U1134 Mean?
This code indicates that a control module is not receiving valid ignition switch position or starter circuit status data over the SCP network. The module expecting this data cannot determine ignition state or starting system activity.
Common Causes
30%
Faulty ignition switch or multifunction switch assembly
25%
Body Control Module (BCM) failing to transmit ignition status
20%
SCP bus communication circuit fault
15%
Damaged wiring between ignition switch and BCM
10%
PCM or receiving module communication failure
Diagnostic Steps
1
Step 1: Monitor ignition switch status on scan tool through all key positions (OFF, RUN, START)
2
Step 2: Check BCM for proper reception of ignition switch signals using module-specific PIDs
3
Step 3: Test ignition switch continuity and resistance through all positions per specifications
4
Step 4: Verify SCP bus voltage and signal integrity during key cycling
5
Step 5: Inspect ignition switch connector and wiring harness for damage or corrosion
Estimated Repair Cost
$200 - $800
Parts + labor, varies by vehicle and location
This code indicates that a control module is not receiving valid ignition switch position or starter circuit status data over the SCP network. The module expecting this data cannot determine ignition state or starting system activity.
The most common cause of U1134 (SCP (J1850) Invalid or Missing Data for Ignition Switch / Starter) is: Faulty ignition switch or multifunction switch assembly
Typical repair costs for U1134 range from $200 to $800, depending on the vehicle, location, and whether you do it yourself or go to a shop.
May cause no-start conditions, intermittent stalling, or failure of accessories to activate properly. Immobilizer systems may be affected, potentially leaving vehicle stranded.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to U1134 to identify the root cause.
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Quick Info
Category
Network
System
Network Communication / Ignition System
Difficulty
Type
Manufacturer
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