P023A

What it means

P023A means the engine control module has detected an open circuit in the control circuit for charge air cooler coolant pump A. This pump circulates coolant through a separate low-temperature loop to cool the intercooler on a turbocharged or supercharged engine. The module commands the pump and sees no expected electrical response, so it sets the fault.

Symptoms

• Engine warning light on
• Reduced power or the engine going into limp mode
• Hot intake air temperatures and poor performance, especially in warm weather or under load
• Intercooler or charge air cooler coolant circuit not circulating
• Possible knocking, retarded timing or poorer fuel economy
• Other stored codes relating to intake air temperature or boost

Possible causes

• Open circuit, chafed or broken wiring in the pump control or supply circuitlikely
• Corroded, loose or damaged connector at the pump or control modulelikely
• Failed charge air cooler coolant pump with an internal open circuitlikely
• Blown fuse or faulty relay supplying the pumppossible
• Poor earth connection in the pump circuitpossible
• Faulty driver circuit inside the engine control modulerare
• Outdated control module software where the manufacturer has issued a known fixrare

How to diagnose

1. Read all stored and pending codes and note the freeze frame data, including intake air temperature, coolant temperature and engine load at the time of setting.
2. Check for related codes covering intake air temperature, boost pressure or the pump supply voltage, and look up any manufacturer bulletins for the model and engine.
3. Visually inspect the pump wiring, connector and routing for chafing, heat damage, water ingress and corrosion.
4. Check the fuse and relay for the pump circuit, as the layout depends on the model and engine.
5. Use a bi-directional diagnostic function, where supported, to command the pump on and listen for or feel it running.
6. With the connector unplugged, check for supply voltage, a good earth and wiring continuity between the pump and the control module, following the manufacturer wiring diagram.
7. Measure the pump's resistance or current draw against the specification for the model, and check coolant level and for air in the low-temperature loop.
8. If the wiring and pump prove good, check the module's connector pins and software status before suspecting the module.

How to fix

• Repair or replace damaged wiring and ensure the circuit has continuity and no short.
• Clean, repair or replace the corroded or damaged connector terminals.
• Replace the charge air cooler coolant pump if it is open circuit or not responding.
• Replace the blown fuse or faulty relay after finding out why it failed.
• Restore a poor earth connection by cleaning and tightening it.
• Update the control module software only if a manufacturer fix is listed, or replace the module as a last resort once everything else is proven good.

Can I keep driving?

Nearby codes

• P0239GenericTurbocharger/Supercharger Boost Sensor B Circuit
• P023BGenericCharge Air Cooler Coolant Pump A Control Circuit Low