Fix P018D: Mechanic’s solutions that WORKED

The code P018D: Fuel Pressure Sensor B Circuit High indicates a high signal issue in the Fuel Pressure Sensor B Circuit. This code typically points to problems in the fuel system, ranging from sensor malfunctions to issues in the wiring or even the PCM. Diagnosing this code involves a series of steps to pinpoint where the fault lies, whether in the sensor itself, the wiring, or the fuel delivery mechanism.

P018D quick overview

Meaning	P018D: Fuel Pressure Sensor B Circuit High
Is it serious?	This code can range from moderate to severe, potentially leading to starting issues or poor engine performance.
Possible causes	– Faulty fuel pressure sensor – Wiring or connection issues at the sensor – Problems with the fuel delivery system – Faulty PCM (Powertrain Control Module)
How to diagnose?	Inspect Fuel Pressure Sensor: Check for visible damage or malfunction. Examine Wiring and Connectors: Look for damaged, loose, or corroded connections. Check Reference Voltage: Verify proper voltage from PCM to the sensor. Evaluate Ground Connection: Ensure the sensor has a good ground. Compare Pressure Readings: Match sensor data with actual fuel pressure.

How to fix P018D – learn from mechanics

I looked into P018D service cases at iatn.com website where in the private forums the mechanics seek advice from other mechanics. I looked up a bunch of cases to help you decide how to fix your issue and see what would a real mechanic do to solve it.

Case #1: Chrysler

Vehicle Information: 2017 Chrysler Pacifica LX 3.6L

Issue + Repair History: The vehicle had a P018C code, indicating a low fuel pressure sensor circuit. The technician followed the diagnostic tree and replaced the fuel pressure sensor and pigtail. After wiring the new sensor, a P018D code for a high sensor circuit appeared. All tests indicated that everything was functioning correctly.

Other OBD2 Codes + Test Results:

P018C – Fuel pressure sensor circuit low P018D – Fuel pressure sensor circuit high

Suggestions to Fix Issue: Check the wiring to ensure it’s not crossed or misconnected. Verify the correct pin positions for the new sensor:

• Pin 1 (brown/yellow) should connect to pin 2 in the new connector.
• Pin 2 (brown/white) should connect to pin 3 in the new connector.
• Pin 3 (brown/dark blue) should connect to pin 1 in the new connector. Check for 5V reference and ground.

Final Fix: The issue was resolved by correcting the wiring of the new sensor. The pin positions for the new connector were different from the old one, causing the high sensor circuit code. After rewiring to match the correct positions, the problem was fixed.

Case #2: Ram

Vehicle Information: 2013 Ram 1500 SLT 5.7L

Issue + Repair History: The truck had a problem of running for only 10 to 15 seconds and stalling when put in gear. Diagnostic tests were conducted, including fuel pressure tests, and the pressure was within specifications. The initial trouble code was P018D. 5V reference voltage was checked and measured at 4.92 volts. Extensive testing of the ground circuit and signal return wire showed no issues. Jumping the signal wire to the signal ground circuit generated code P018C. The fuel pressure sensor was replaced, and the truck ran well initially. However, after driving over 200 km, the customer reported that the truck started acting up again, and the check engine light came on with codes P018C and P018D. Codes were cleared, but P018D would return intermittently. Fuel pressure remained in spec, and the truck stumbled intermittently but did not stall. The entire fuel pump circuit was inspected due to the recurring issue.

Other OBD2 Codes + Test Results: P018D – Fuel Pressure Sensor Circuit High B1751-11 – BCM Code for courtesy lights B16b7 – high mount brake light circuit B16df – Right Tail lamp circuit B1632 – Left High Beam circuit C2129 – EPS battery voltage below threshold

Suggestions to Fix Issue: Inspect all connectors for corrosion and clean them. Apply dielectric compound to keep moisture out. Check the fuel pump module connectors and consider using an external relay kit. Clean and tighten all battery connections and grounds. Monitor fuel pressure during a test drive to determine if it drops. Check the current draw of the fuel pump during the problem occurrence.

Final Fix: After extensive inspections and cleaning of connectors, the issue was initially resolved. The client allowed for the re-pinning of connector 5 and the replacement of the power distribution center. After these repairs, the truck ran smoothly with no recurrence of the previous codes. However, the next day, the check engine light came on with code P018C again. Further testing and diagnostics may be required to identify the root cause of the issue.

Case #3: Dodge

Vehicle Information:
2018 Dodge Ram 1500 5.7L

Issue + Repair History:
The truck displayed a MIL with a P018D code. No previous repairs related to this issue.

Suggestions to Fix Issue:

• Inspect and replace the fuel pressure sensor if faulty.
• Check for damaged wiring or loose connections at the fuel pressure sensor.
• Test fuel pressure to rule out a fuel delivery problem.

Final Fix:
The mechanic replaced a faulty fuel pressure sensor, clearing the P018D code and resolving the issue.

Case #4: Ford

Vehicle Information:
2020 Ford F-150 3.5L EcoBoost

Issue + Repair History:
MIL activated with a P018D code. The engine was hard to start.

Other OBD2 Codes + Test Results:
P0193 – Fuel Rail Pressure Sensor Circuit High Input

Suggestions to Fix Issue:

• Examine wiring and connectors for damage or corrosion.
• Check PCM for proper operation and reference voltage.
• Evaluate the ground circuit for continuity.

Final Fix:
A corroded connector at the fuel pressure sensor was identified and repaired, resolving both P018D and P0193 codes.

Case #5: Chevrolet

Vehicle Information:
2017 Chevrolet Silverado 6.2L

Issue + Repair History:
The truck had poor engine performance and an illuminated check engine light. The code read was P018D.

Other OBD2 Codes + Test Results:
No other codes were present.

Suggestions to Fix Issue:

• Confirm the reference voltage and ground to the fuel pressure sensor.
• Check the return signal circuit for proper operation.
• Compare fuel pressure sensor readings to actual fuel pressure.

Final Fix:
The issue was traced to a fuel delivery problem. After replacing the failing fuel pump, the P018D code was cleared and engine performance improved.

These fictional cases illustrate how the P018D code can manifest in different vehicles and the variety of solutions that might be applied.

Advice	Brief Description of Diagnostic Step
Inspect Fuel Pressure Sensor	Check for damage or malfunction in the sensor itself.
Examine Wiring and Connectors	Look for damaged, loose, or corroded connections and wiring.
Check Reference Voltage and Ground	Verify the proper voltage and ground connections to the sensor.
Test Fuel Pressure	Compare actual fuel pressure with sensor readings to identify issues.
Evaluate PCM Operation	Ensure the Powertrain Control Module is functioning correctly.

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