P2603
Coolant Pump A Control Circuit High
2016-2016 Cadillac ATS 2.5L I4
Moderate SeverityPowertrainGeneric (SAE)
The 2016 Cadillac ATS is equipped with a 2.5L inline-4 engine. Below you'll find detailed p2603 diagnostic code information including labor time estimates, cost ranges, and technician notes specific to this engine configuration.
Description
High voltage on auxiliary coolant pump circuit.
Symptoms
- Check engine light
- Pump runs constantly
Common Causes
- Open ground
- Short to power
- Control module issue
Diagnostic Steps
- Check ground circuit
- Measure voltage
Repair Notes
Repair wiring or replace pump.
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
P2603 on Other Vehicles
Common Questions
What does code P2603 mean on a 2016-2016 Cadillac ATS?
P2603 stands for "Coolant Pump A Control Circuit High". High voltage on auxiliary coolant pump circuit.
What are the symptoms of P2603 on a Cadillac ATS?
Common symptoms of P2603 include: Check engine light, Pump runs constantly.
What causes P2603 on a 2016-2016 Cadillac ATS?
Common causes of P2603 include: Open ground, Short to power, Control module issue.
Last updated: March 2026