Faulty charge air cooler coolant pump (internal short or failed motor or driver); Damaged, chafed or shorted wiring to the pump control circuit; Corroded, loose or water-damaged connector at the pump or control unit; Blown fuse or faulty relay supplying the pump, where fitted; Poor earth connection or low supply voltage to the pump circuit; Fault inside the engine control unit driver circuit.

P023B

Charge Air Cooler Coolant Pump A Control Circuit Low.

Generic
Powertrain
Generic code
Medium severity

How this code is built

P: SystemPowertrain
0: Defined bySAE, the same on every car
2: AreaFuel and air metering (injector circuit)
3B: FaultThe specific fault in that area

What it means

P023B means the engine control unit has detected a low voltage or signal state in the control circuit for charge air cooler coolant pump A. This pump circulates coolant through a liquid-cooled intercooler, and the control unit saw the circuit read lower than expected when it commanded or monitored the pump. The exact circuit layout and pump control method vary by model and engine.

Symptoms

Engine warning light on
Reduced engine power or limp mode
Hot intake air and poor performance, especially under load or in hot weather
Pump not running or not audible when it should be
Possible other charge air temperature or boost related codes stored

Possible causes

Faulty charge air cooler coolant pump (internal short or failed motor or driver)likely
Damaged, chafed or shorted wiring to the pump control circuitlikely
Corroded, loose or water-damaged connector at the pump or control unitlikely
Blown fuse or faulty relay supplying the pump, where fittedpossible
Poor earth connection or low supply voltage to the pump circuitpossible
Fault inside the engine control unit driver circuitrare

How to diagnose

Read all stored codes and freeze frame data, noting engine load, temperatures and battery voltage when the fault set, and check for related codes.
Check the battery condition and charging voltage, as low system voltage can upset pump circuit monitoring.
Visually inspect the pump wiring, connector and earth points for chafing, heat damage, corrosion, water ingress or looseness.
Check the fuse and relay for the pump circuit using the manufacturer's wiring diagram for that model.
Use a scan tool with bidirectional controls, if supported, to command the pump on and listen or feel for operation.
With the connector unplugged, test the supply, earth and control wire for continuity, short to earth and short to supply against the wiring diagram.
Check the pump's electrical resistance or current draw against manufacturer specification, as the method depends on the pump type.
Check the coolant level and look for air in the intercooler circuit, as this can affect pump operation.

How to fix

Replace the charge air cooler coolant pump if it fails electrical or operational tests.
Repair or replace damaged wiring, and secure any loose harness routing.
Clean or replace corroded or damaged connectors and terminals.
Replace the blown fuse or faulty relay after finding the reason it failed.
Restore good earth and supply connections.
Top up and bleed the intercooler coolant circuit to the manufacturer's procedure, then clear the code and road test to confirm it does not return.

Can I keep driving?

Medium severity

The car can usually be driven carefully for a short time, but expect reduced power and hot intake air, which can raise the risk of knock or engine strain under load. Get it checked soon and avoid heavy loads or hot-weather hard driving until repaired.

Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.