OBD-II Diagnostic Trouble Code
P1654 — AC Refrigerant Pressure Switch Performance
P1654 is a manufacturer-specific code that commonly means the AC refrigerant pressure switch or sensor signal does not match what the ECM expects for current operating conditions. Meaning can vary by OEM.
Severity 1/5
Less common on commercial trucks
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Severity
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AC Refrigerant Pressure Switch Performance
Code
P1654
Category
Powertrain
Subsystem
Cooling
Truck-relevant
Less common
What this means for truckers
Low severity. The vehicle is safe to drive to your next planned stop. Address at your next regular service.
Before you replace parts — try this first
P1654 on the Cooling system is most often faulty ac pressure switch or sensor — not a dead part. On commercial diesels especially, work these in order before spending money on parts:
- Confirm the symptoms. Match what your truck is doing to the Symptoms section below. If the code is set but the symptoms are not there, clear the code and re-test after a drive cycle — it may not return.
- Clean and dry the sensor connector. Water, road salt, or oil seeping into a connector is the #1 fake sensor failure. Disconnect, look for green corrosion or moisture, spray with electrical contact cleaner, dry, reseat. Many faults clear here for $0.
- Inspect the wiring harness. Trace the wire from the sensor toward the ECM — look for chafing against the engine block, melted insulation near the turbo or exhaust, or pinch points where a clamp has rubbed through.
- Test the sensor before swapping it. Most Common Causes (below) list the expected voltage or resistance range — a $20 multimeter saves a $300 sensor swap that does not fix the problem.
- Only then, replace the part. Use the OEM or a tier-1 aftermarket. Cheap sensors throw the same code in two weeks.
Symptoms
AC not cooling or the compressor cycling oddly, cooling fan running more than normal, and a check-engine light. The engine itself usually runs normally.
Common causes
- CommonFaulty AC pressure switch or sensor ($100–$300)
- CommonLow or overcharged refrigerant ($150–$500)
- OccasionalWiring or connector fault ($80–$300)
- OccasionalRestricted condenser or failed condenser fan ($300–$1200)
How to fix
Check AC pressures with gauges and compare to the sensor reading
When to use: First step
Correct the refrigerant charge
When to use: When charge is wrong
Replace the pressure switch or sensor
When to use: When the sensor does not match gauge readings
Inspect condenser and fan
When to use: When high-side pressure is too high
Affects most
No specific vehicle pattern found in our complaint database. This code can appear on any vehicle that supports OBD-II diagnostics.
Related
- → Browse all DTC trouble codes
- → Decode a VIN to check codes for your truck
- → Owner-operator maintenance guides
- → P1607 — Internal Control Module Performance
- → P1635 — 5 Volt Reference 1 Circuit
- → P1638 — 5 Volt Reference 2 Circuit
- → P1690 — Wastegate Control Boost Pressure Out of Range
- → P1693 — Glow Plug Control Module Communication Lost
Frequently Asked Questions
Can I drive with code P1654?
Yes — P1654 is severity 1. The vehicle is safe to drive to your next planned stop. Address at your next regular service. The check engine light will stay on until the underlying issue is fixed and the ECM monitors clear.
How much does it cost to fix P1654 on a commercial truck?
Total repair cost ranges $80–$1200 depending on the root cause. The cheapest fix is usually the first one listed below — Faulty AC pressure switch or sensor — which is also the most common. On commercial trucks the cost is usually higher than passenger vehicles due to part availability and shop labor rates ($120–185/hour at most truck shops, vs $90–130 at general auto shops). DIY-capable fixes (sensors, hoses, filters) are at the low end; major component replacements (turbo actuator, high-pressure fuel pump, transmission solenoid pack) are at the high end. Always diagnose with a scan tool BEFORE replacing parts — guessing wrong on a $1,500 turbo actuator when the actual issue was a $30 boost hose is a common expensive mistake.
Will P1654 fail a DOT inspection?
P1654 is generally not a direct DOT inspection fail item by itself. Inspectors focus on safety-critical systems (brakes, steering, tires, lights, hours-of-service). However, the check engine light alone can trigger additional inspection scrutiny. Best practice: fix the code and clear it before a planned inspection.
What's the difference between P1654 and related codes?
P1654 is closely related to: P1607 (Internal Control Module Performance), P1635 (5 Volt Reference 1 Circuit), P1638 (5 Volt Reference 2 Circuit), P1690 (Wastegate Control Boost Pressure Out of Range). These codes share the same subsystem (cooling) and often appear together. If you see this code, scan for the full code list — fixing the root cause usually clears multiple companion codes at once. If only P1654 is set without the companions, the issue is more isolated.
How do I prevent P1654 from coming back after a repair?
For P1654 (AC Refrigerant Pressure Switch Performance), prevention centers on the cooling system. Service cooling system at OEM interval. Use the correct coolant type — modern HD engines need ELC (Extended Life Coolant), not green/conventional. Pressure-test cap and system annually.