Ignition 1 Power Circuit Low Voltage
2016-2016 Cadillac ATS 2.5L I4
The 2016 Cadillac ATS is equipped with a 2.5L inline-4 engine. Below you'll find detailed p1634 diagnostic code information including labor time estimates, cost ranges, and technician notes specific to this engine configuration.
Description
The PCM detected low voltage on the Ignition 1 power supply circuit.
Symptoms
- Check Engine Light
- Engine stalling
- Erratic gauges
- Multiple system malfunctions
Common Causes
- Faulty ignition switch
- Blown Ignition 1 fuse
- Corroded connections
- Damaged wiring in ignition circuit
Diagnostic Steps
- Test Ignition 1 circuit voltage at PCM
- Check Ignition 1 fuse
- Test ignition switch
- Inspect wiring and connectors
Repair Notes
Check fuse and ignition switch. Repair wiring as needed.
Related Codes
Other Powertrain Codes
- P0001Fuel Volume Regulator Control Circuit/Open
- P0002Fuel Volume Regulator Control Circuit Range/Performance
- P0003Fuel Volume Regulator Control Circuit Low
- P0004Fuel Volume Regulator Control Circuit High
- P0010Intake Camshaft Position Actuator Circuit/Open Bank 1
- P0011Intake Camshaft Position Timing Over-Advanced Bank 1
- P0012Intake Camshaft Position Timing Over-Retarded Bank 1
- P0013Exhaust Camshaft Position Actuator Circuit/Open Bank 1
- P0014Exhaust Camshaft Position Timing Over-Advanced Bank 1
- P0015Exhaust Camshaft Position Timing Over-Retarded Bank 1
P1634 on Other Vehicles
Common Questions
What does code P1634 mean on a 2016-2016 Cadillac ATS?
P1634 stands for "Ignition 1 Power Circuit Low Voltage". The PCM detected low voltage on the Ignition 1 power supply circuit.
What are the symptoms of P1634 on a Cadillac ATS?
Common symptoms of P1634 include: Check Engine Light, Engine stalling, Erratic gauges, Multiple system malfunctions.
What causes P1634 on a 2016-2016 Cadillac ATS?
Common causes of P1634 include: Faulty ignition switch, Blown Ignition 1 fuse, Corroded connections, Damaged wiring in ignition circuit.
Last updated: March 2026