P023A — Charge Air Cooler Coolant Pump Control Circuit Open

powertrain (engine/transmission)

Is it safe to drive?

Limited driving while repair is arranged P023A does not always cause immediate failure, but loss of charge-air coolant circulation can produce high charge-air temperatures, reduced power, or derating. Avoid heavy load if temperatures remain stable, and stop driving if overheating, temperature warnings, or severe power loss occurs.

Typical symptoms

  • The check-engine light may illuminate with P023A stored in the powertrain system.
  • The charge air cooler coolant pump may remain off when the scan tool shows it is being commanded.
  • Charge-air temperature may rise higher than expected, particularly during boost or hard acceleration.
  • Reduced boost, power limitation, or an engine derate may occur if charge-air temperatures become excessive.
  • In some vehicles, inadequate coolant circulation can contribute to elevated coolant temperature or an overheating condition.

Common causes

  • P023A can be caused by an open in the charge air cooler coolant pump supply or ground wiring.
  • Corroded, loose, or damaged pump connector terminals can interrupt the control circuit.
  • A failed pump motor or internal driver can create the open-circuit condition reported by P023A.
  • A blown fuse, faulty relay, or failed power transistor may prevent the pump from receiving its command.
  • Chafed wiring near hot or rotating components can expose the pump harness and cause P023A.
  • A poor electrical ground at the pump or control module can make the circuit appear open.

How to diagnose with an OBD scanner

  1. Confirm P023A with an OBD scanner Connect an OBD scanner using ELM327 or AIScanAuto and read stored, pending, and permanent codes. Confirm that P023A is active, save freeze-frame data, and check whether the scanner shows a pump command or circuit-status test.
  2. Inspect the pump and wiring Locate the charge air cooler coolant pump and examine its connector, wiring harness, and ground points. Look for corrosion, coolant contamination, loose terminals, pin damage, and chafing near hot or moving components.
  3. Check power, ground, and pump operation Use the vehicle wiring diagram to identify the pump supply, command, and ground circuits. With the pump commanded on, measure voltage and current. Normal voltage with no current suggests a failed pump; no command or output voltage points toward the relay or control module.
  4. Isolate an open circuit Perform voltage-drop and continuity tests at the pump connector and along the harness. Repair any open wires, poor grounds, or damaged terminals before condemning the pump or module.
  5. Repair and verify the fault Replace the defective pump, fuse, relay, connector, or internal driver as testing indicates. Clear the code with the scanner, command the pump, monitor coolant and charge-air temperatures, and road-test to confirm P023A does not return.

Approximate repair cost

A typical independent-shop range is USD 250-900 for diagnosis and repair of the coolant pump, wiring, connectors, relay, or related driver. Figures are estimates and vary by region.

Common questions

Does P023A always mean the coolant pump has failed?

No. P023A identifies an open control circuit, so a pump failure is possible but not proven; wiring, connectors, power, ground, relays, and control-module drivers must also be tested.

Can the vehicle be driven with P023A?

Yes, cautiously, if coolant and charge-air temperatures remain normal and the engine is not being derated. Stop driving if temperature rises, warnings appear, or power decreases substantially.

What electrical readings confirm the P023A fault?

Service information should specify the expected pump voltage and current. Missing output voltage points upstream, while voltage with abnormal or zero current points to the pump or its internal driver.

What parts may need repair for P023A?

Repair may involve the charge air cooler coolant pump, corroded terminals, damaged harness, relay, fuse, or the module's internal driver. Confirm the open circuit before replacing components.

When the engine control module detects that the electrical circuit responsible for the charge air cooler coolant pump has stopped conducting current, it logs OBD2 code P023A. This fault falls within the powertrain category and belongs to the group of codes that monitor the engine cooling and forced-induction temperature regulation systems. In practical terms, the ECU expects to see a complete electrical path from the control module through the wiring harness to the coolant pump motor and back. When that path is interrupted, the module registers an "open circuit" condition.

The charge air cooler (also called an intercooler) relies on coolant circulation to dissipate heat from compressed intake air. If the coolant pump that drives this loop stops working properly, intake air temperatures climb, which degrades engine performance and efficiency. To avoid triggering this code from a single glitchy reading, the control module requires the fault condition to repeat under specific operating conditions before illuminating the Check Engine light. This is why freeze frame data saved alongside P023A is so valuable—it captures engine load, RPM, coolant temperature, and vehicle speed at the exact moment the fault was detected, giving you a starting point for your investigation.

Common Symptoms of P023A

P023A rarely announces itself with dramatic fanfare. More often, the signs are subtle and build gradually:

  • Check Engine Light remains illuminated on the dashboard
  • Engine temperature gauge reads lower than normal or fails to reach typical operating temperature
  • Cabin heating feels weak or inconsistent, especially during cold weather
  • In severe cases, the engine may overheat unexpectedly during heavy load conditions
  • Fuel economy drops noticeably compared to normal driving patterns

What Causes P023A

The underlying issue is always an electrical open somewhere in the charge air cooler coolant pump control circuit, but several specific problems can create that open:

  • Wiring harness damage—broken, chafed, or melted wires in the circuit
  • Coolant pump motor failure internally (the motor windings open up)
  • Blown fuse protecting the circuit from overcurrent
  • Connector problems—unplugged harness, backed-out terminals, or corrosion blocking current flow
  • Faulty cooling fan motor or associated relay
  • Defective coolant temperature sensor providing incorrect feedback to the ECU
  • Thermostat stuck in either the open or closed position
  • General wiring faults elsewhere in the sensor circuit that affect this loop

How to Diagnose P023A

Effective diagnosis follows a logical progression from simple checks to more involved testing:

  1. Connect an OBD2 scanner, verify P023A is stored, and record all freeze frame data—this tells you what engine conditions coincided with the fault.
  2. Scan for additional trouble codes. Related DTCs often point directly to the root cause rather than the symptom.
  3. Consult manufacturer technical service bulletins for your specific make, model, and year—many P0xxx codes have documented software updates or known fixes.
  4. Perform a visual inspection of all wiring and connectors associated with the charge air cooler coolant pump circuit, looking for damaged insulation, bent pins, corrosion buildup, or loose connections.
  5. Use a multimeter to conduct end-to-end continuity testing on the circuit while gently wiggling the harness—intermittent opens reveal themselves through fluctuating readings.
  6. Monitor live coolant temperature data during a warm-up cycle; the temperature should rise smoothly to normal operating range, and the thermostat should open at the specified temperature.
  7. After clearing the code, drive the vehicle through conditions matching the freeze frame data and verify that P023A does not reappear.

Repair Options and Costs

Before committing to expensive component replacement, address the most accessible and common failure points first:

  • Cooling system repair (coolant pump, cooling fan, or radiator replacement): $300–$1,200
  • Coolant temperature sensor replacement: $100–$300
  • Thermostat replacement: $150–$400

These figures represent typical parts and labor at independent repair shops in the United States. The wide range reflects different vehicle architectures and labor rates across regions.

Driving Safety Verdict

Severity level: Caution. P023A indicates a real problem with your engine cooling system, but the vehicle remains drivable for short distances if you monitor the temperature gauge closely. A stuck-open thermostat primarily hurts fuel economy, while a complete pump failure risks engine overheating. At the first sign of overheating—coolant warning light, steam from the hood, or temperature gauge hitting the red zone—pull over immediately and shut off the engine. Continued driving with an overheating engine causes catastrophic head gasket failure and can permanently damage internal components.

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