P023B — Charge Air Cooler Coolant Pump Control Circuit Low #

Note: The code description may vary depending on the vehicle manufacturer.

• Charge Air Cooler Coolant Pump Control Circuit Low (Generic/Most OEMs)
• Intercooler Coolant Pump Control Circuit Low (Ford)
• Intercooler Pump Control Circuit Low Input (GM/Chevrolet)
• Low Voltage in Charge Air Cooler Pump Control Circuit (BMW)

Summary of DTC P023B #

The P023B diagnostic trouble code indicates that the engine control module (ECM) or powertrain control module (PCM) has detected a low voltage condition in the control circuit of the charge air cooler coolant pump. This pump is responsible for circulating coolant through the charge air cooler (also known as an intercooler) to reduce the temperature of the intake air, improving engine performance and efficiency. A low control circuit signal can result from electrical faults, pump failure, or module issues. If left unresolved, this can lead to increased intake air temperatures, reduced power, and potential engine stress. Prompt diagnosis and repair are essential to maintain optimal engine operation and prevent further complications.

Common Symptoms for Code P023B #

When the P023B code is stored, drivers may notice a range of symptoms, from mild to more pronounced. These symptoms are often related to engine performance, especially under load or during warm weather. Here’s what to watch for:

• Reduced engine power — The engine may feel sluggish, particularly during acceleration.
• Illuminated check engine light (CEL) — The most obvious alert, typically displayed on the dashboard.
• High intake air temperatures — Often visible if the vehicle has a performance monitor or via scan tool data.
• Poor fuel economy — The engine may use more fuel than usual.
• Knocking or pinging under load — Detonation risk increases with hotter intake air.
• Intermittent limp mode — Some vehicles may limit engine output to protect components.

Likely Causes for Code P023B #

The P023B code can be triggered by several factors, most of which are electrical or mechanical in nature. Understanding these helps prioritize your diagnostic approach. Here are the most common causes, ordered by how frequently they occur:

1. Faulty charge air cooler coolant pump — The pump itself may have failed electrically or mechanically.
2. Wiring issues — Broken, corroded, or shorted wires/connectors in the pump control circuit.
3. Bad charge air cooler coolant pump relay — The relay may not be sending proper voltage to the pump.
4. Low system voltage — Weak battery or charging system problems affecting circuit voltage.
5. Faulty PCM/ECM — Rarely, the control module itself may have an internal fault.

Diagnostic Steps for Code P023B #

Diagnosing P023B requires a systematic approach, starting with the basics and moving to more specific tests. Proper tools include a digital multimeter, scan tool, and—if possible—OEM wiring diagrams. Here’s a proven step-by-step method:

• Step 1: Verify the code with a scan tool and check for related codes (especially those for coolant pumps, intake air temperature, or low voltage).
• Step 2: Visually inspect the charge air cooler coolant pump and its wiring for damage, corrosion, or loose connectors.
• Step 3: Test the pump’s power and ground circuits with a multimeter. Ensure voltage is present at the pump connector when commanded ON.
• Step 4: Check the relay (if equipped) by swapping with a known-good relay or testing continuity/function.
• Step 5: Activate the pump via scan tool bi-directional controls (if available) to verify operation.
• Step 6: If all else checks out, test for continuity between the ECM/PCM and the pump control circuit.
• Step 7: Consult OEM service information for any technical service bulletins (TSBs) or software updates related to this code.

Potential Repairs for Code P023B #

Once the root cause of the P023B code is found, repairs should be targeted and thorough. Always clear the code and retest after repairs to ensure the issue is resolved. Depending on your findings, you may need to:

• Replace the charge air cooler coolant pump if it fails electrical or mechanical tests.
• Repair or replace damaged wiring/connectors in the pump control circuit.
• Replace a faulty pump relay if it does not operate or passes excessive resistance.
• Address low battery or charging system voltage by servicing the battery or alternator as needed.
• Replace or reprogram the PCM/ECM only if all other causes are eliminated and OEM testing confirms module failure.

Can You Drive with Code P023B? #

Limited — With caution: While it is sometimes possible to drive with the P023B code present, it is not recommended for extended periods. The engine may run hotter than normal, risking power loss and in rare cases, engine damage (especially in turbocharged or high-performance vehicles). If symptoms are severe or the check engine light is flashing, avoid driving until repairs are made. If you must drive, keep engine loads light and monitor performance closely.

Vehicles Most Commonly Affected by Code P023B #

The P023B code is more commonly reported in vehicles with forced induction (turbocharged or supercharged engines) that use a liquid-to-air charge air cooler with an electric coolant pump. Models where this code is frequently encountered include:

• Ford F-Series EcoBoost (F-150, F-250, Expedition)
• Chevrolet Silverado/GMC Sierra (Turbo models)
• BMW 3-Series, 5-Series, and X-series (turbocharged engines)
• Volkswagen Golf GTI, Golf R, and Audi S/RS models
• Mercedes-Benz C-Class, E-Class (AMG and turbocharged variants)

Common Mistakes & Best Practices with P023B #

When troubleshooting P023B, some pitfalls are surprisingly common. Avoiding these can save time, money, and future headaches. Here’s what technicians and DIYers should remember:

• Don’t replace the pump without verifying power and ground at the connector — wiring faults are common!
• Don’t overlook battery and charging system health — low voltage can mimic circuit issues.
• Always clear codes and perform a road test after repairs to confirm the fix.
• Consult OEM wiring diagrams and TSBs for your specific vehicle — there may be unique connector or routing issues.
• Avoid bypassing the relay or hard-wiring the pump — this can cause further electrical problems and void warranties.

Quick FAQ for Code P023B #

Q: Is P023B a critical code?
A: While not immediately catastrophic, P023B should be addressed promptly to avoid increased intake temperatures, performance losses, and potential engine stress. Ignoring it can lead to more expensive repairs down the line.

Q: Will clearing the code fix the problem?
A: Clearing the code without addressing the underlying fault will not resolve the issue. The code will return as soon as the control module detects the low circuit condition again.