P023A: Charge Air Cooler Coolant Pump A Control Circuit/Open

Some engines cool the charge air with a coolant-to-air cooler in its own low-temperature circuit, driven by an electric pump – GM uses this on supercharged V8s such as the LT4 (Camaro ZL1, Corvette Z06, CTS-V) and LT5 (Corvette ZR1). P023A means GM's driver diagnosis has found an open circuit (more than 200 kΩ between output and ground with the low-side driver off). Bundled conditions: main relay at least 11 V, ignition above 5 V; 50 of 63 samples set the code with the warning light in the first trip on 2018–2019 engines, older modules need two trips. Without the pump the charge air gets hot and boost is limited.

Symptoms

• Check engine light on
• Loss of power under load or in heat (boost limited)
• Follow-up code P026A possible

Most likely causes

• Wire or connector at the pump open (front area, corrosion)
• Pump faulty (motor or electronics)
• Fuse, pump relay or supply missing
• Driver stage in the engine module faulty

What to check, in order

Start with the simplest. You can tick off each step.

1. With the engine cold, check the coolant level; never do this when the system is hot
2. Check the continuity of the wire between the component and the control module.
3. Check the actual temperature in live data
4. Make sure the fan comes on when it should
5. Check the thermostat and connector
6. Measure the sensor and replace it if its readings do not make sense

Good to know

• Repair difficulty: medium
• It can trigger limp mode.
• It affects emissions.

What each character of P023A means

• P: Powertrain: engine and transmission
• 0: Generic code: same on every make
• 2: Fuel injection
• 3A: Specific fault in that system

Frequently asked questions

Can I keep driving with code P023A?

Watch the temperature gauge. If it climbs or a warning appears, stop the car in a safe place and turn off the engine: overheating can cause serious damage.

What causes code P023A?

The most common causes are: wire or connector at the pump open (front area, corrosion); pump faulty (motor or electronics); fuse, pump relay or supply missing.

Related codes

• P023BCharge Air Cooler Coolant Pump A Control Circuit Low
• P023CCharge Air Cooler Coolant Pump A Control Circuit High
• P026ACharge Air Cooler Efficiency Below Threshold
• P026ECharge Air Cooler Coolant Pump A Performance

Sources

• law.cornell.edu: 13 CCR 1968.2
• gsi.ext.gm.com: 18OBDG03A Engine Diagnostics
• gsi.ext.gm.com: 19OBDG03A Diagnostics
• gsi.ext.gm.com: 16OBDG05 Engine Diagnostics

Values and procedures vary by manufacturer. If it affects brakes, steering, fuel or high voltage, see a professional. Updated: 2026-11-04. How we build these pages.