P1652 Fuel Pump Monitor Circuit Low
The P1652 code indicates that the Powertrain Control Module (PCM) has detected an abnormally low voltage signal on the fuel pump monitor circuit. This circuit provides feedback from the Fuel Pump Driver Module (FPDM) or directly from the fuel pump circuit to confirm operational status. A low input suggests an open circuit, a short to ground, or an internal FPDM fault preventing proper signal modulation.
01. Most Common Causes
- Faulty Fuel Pump Driver Module (FPDM)
- Open or short-to-ground in the monitor circuit (FPDM to PCM signal wire)
- Corroded, loose, or damaged connectors at the FPDM or PCM
- Fuel pump with internal short to ground
- Internal PCM failure (rare)
02. Symptoms You Will Notice
- Engine cranks but does not start
- Engine stalls or runs poorly
- Check Engine Light illuminated
03. Step-by-Step Diagnosis
Scan for additional codes and note freeze frame data
Visually inspect FPDM and PCM connectors for corrosion or damage
Test the monitor circuit for continuity and shorts to ground using a multimeter
Check fuel pump operation and voltage supply at the pump connector
If all else is normal, test or replace the FPDM; if problem persists, test PCM
1. Frequently Asked Questions
Is it safe to drive?▼
No, this code indicates a high-severity fuel system fault that can cause stalling or a no-start condition, making the vehicle unsafe to drive. Have it towed to a repair shop.
How much does it cost to fix?▼
Repair costs typically range from $200 to $800, depending on whether the FPDM, fuel pump, or wiring needs replacement. Diagnostic fees are extra.