Fix P062B: Mechanic’s solutions that WORKED

The P062B: Internal Control Module Fuel Injector Control Performance code indicates a problem with the fuel injector control system, managed by the vehicle’s internal control module, typically the ECM. This code suggests that the ECM is not controlling the fuel injectors properly, which can lead to issues with engine performance and efficiency.

P062B quick overview

Meaning	P062B: Internal Control Module Fuel Injector Control Performance
Is it serious?	This code can be serious as it may affect engine performance and could lead to more significant issues if not addressed.
Possible causes	– Faulty Engine Control Module (ECM) – Poor electrical connections to the fuel injectors – Faulty fuel injectors – Wiring issues, including damaged or corroded wires – Problems with the vehicle’s fuel system
How to diagnose?	Inspect Wiring and Connectors: Check for damaged or corroded wiring and connectors, especially around the fuel injectors. Test Fuel Injectors: Perform diagnostic tests on the fuel injectors to ensure they are operating correctly. Examine ECM: Inspect the Engine Control Module for any signs of damage or malfunction. Check Fuel Quality: Verify the quality of the fuel in the vehicle. Reprogram or Replace ECM: If other steps do not resolve the issue, consider reprogramming or replacing the ECM.

How to fix P062B – learn from mechanics

I looked into P062B 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: Nissan

Vehicle Information: 2021 Nissan Titan S 5.6L

Issue + Repair History:

• No start condition when cold.
• Initially, cycling the key a few times would start the engine, suggesting a low-pressure pump or check valve issue.
• At 11,585 miles, the dealership replaced the PCM, but the issue persisted.
• The vehicle requires key on for 20+ minutes before starting.
• Releasing fuel pressure from the high-pressure pump feed line enables the engine to start and keep running.
• P062B code detected about 4 times, but it’s not a hard code.

Suggestions to Fix Issue:

• Check the fuel rail pressure sensor readings under different conditions.
• Consider that the engine might start on low pressure if the high-pressure system is bled off.
• Explore different strategies for fuel pressure control as used by different manufacturers.
• Compare the actual fuel pressure to the commanded pressure when the engine runs.

Final Fix: The problem was linked to a faulty relay, identified after an email chain with the last dealership that worked on the vehicle. This relay issue was causing the engine to flood and die in cold conditions. The resolution was based on the P062B code, leading to the identification and replacement of the problematic relay.

Case #2: Infiniti

Vehicle Information: 2012 Infiniti QX56 5.6L

Issue + Repair History:

• Misfire and P062b code (Fuel injector module).
• Balance test on injectors showed all injectors are functioning properly.
• Spark plugs and coils in good condition.
• No head gasket leak, good vacuum reading at idle, and no vacuum leak.
• Battery and charging system functioning well.
• ECM and battery connections are good.

Suggestions to Fix Issue:

• Check injector current ramp waveform with a low amp clamp and scope.
• Test injector trigger wires at the ECM with a test light or measure injectors resistance starting at the ECM harness connector.
• Check power to each injector and their resistance (1.44-1.73 ohms).
• Inspect each connector with a noid light.
• Check powers and grounds to the ECM.
• Consider replacing the ECM if powers and grounds are good.
• Use a DSO to monitor the amp ramp and voltage trace of each injector, especially the voltage drop on the ground side.

Final Fix: The issue was resolved by disconnecting both battery cables and touching them together for 2 days. After a test drive of 56 miles, no code occurred and the vehicle ran smoothly. A new ECM update was installed for the customer, as he drives a lot. The part cost was $1,467.00

Case #3: GMC

Vehicle Information: 2013 GMC Sierra 4.3L

Issue + Repair History:

• Rough running engine and poor acceleration.
• Diagnostic code P062B present.
• Recent repairs include new fuel injectors and a mass air flow sensor replacement.
• No issues with fuel quality detected.

Suggestions to Fix Issue:

• Check the electrical connections at the fuel injectors for corrosion or poor contact.
• Perform a resistance test on the fuel injectors to ensure they are within specifications.
• Examine the ECM for any visible damage or signs of overheating.
• Test the ECM’s communication with other vehicle modules using a scan tool.
• If no other issues are found, consider ECM replacement.

Final Fix: The issue was traced back to a faulty ECM. After confirming that the fuel system components were functioning correctly, the ECM was replaced, resolving the rough running condition and clearing the P062B code.

Case #4: Buick

Vehicle Information: 2014 Buick Enclave 3.6L

Issue + Repair History:

• Engine misfiring with rough idle.
• Code P062B (Internal Control Module Fuel Injector Control Performance) present.
• Spark plugs and ignition coils were recently replaced.
• Fuel quality checked and found to be good.

Suggestions to Fix Issue:

• Inspect the wiring harness for any signs of damage or corrosion, especially near the fuel injectors.
• Perform a thorough check of the fuel injector connectors and terminals for proper connection.
• Test the fuel injectors for correct operation and resistance.
• Check the ECM for any signs of damage or water ingress.
• Consider ECM reprogramming or replacement if other diagnostics do not resolve the issue.

Final Fix: The problem was resolved by replacing the ECM. Diagnostics showed no issues with wiring or injectors, leading to the conclusion that the ECM was faulty. The replacement of the ECM eliminated the misfire and the P062B code did not return.

Case #5: Ford

Vehicle Information: 2016 Ford F-150 5.0L

Issue + Repair History:

• Engine stalling and restarting difficulty.
• P062B code detected.
• Fuel pump and filter recently replaced.
• No apparent issues with fuel quality.

Suggestions to Fix Issue:

• Conduct a detailed inspection of the fuel injector wiring and connectors for any signs of wear or damage.
• Test the fuel pressure to ensure it is within the manufacturer’s specified range.
• Check the functionality of the fuel injectors using a diagnostic scanner.
• Inspect the ECM for any physical damage or signs of electrical issues.
• Consider reprogramming or replacing the ECM if all other diagnostics are inconclusive.

Final Fix: Found that the issue was related to a software glitch in the ECM. Reprogramming the ECM with the latest software update from Ford resolved the stalling issue, and the P062B code did not reappear.

Advice	Brief Description of Diagnostic Step
Inspect Wiring and Connectors	Check the wiring harness, especially near fuel injectors, for damage, corrosion, or loose connections.
Test Fuel Injector Functionality	Use a diagnostic scanner to test the operation and resistance of the fuel injectors to ensure they are functioning properly.
Check Fuel Quality	Verify the quality of the fuel in the system to rule out issues related to contaminated or poor-quality fuel.
Examine the ECM	Inspect the Engine Control Module (ECM) for physical damage, signs of electrical issues, or water ingress.
Consider ECM Reprogramming or Replacement	If other diagnostics are inconclusive, reprogram the ECM with the latest software update or consider replacing it if faulty.
Check Fuel Pressure	Ensure the fuel pressure is within the manufacturer’s specified range, indicating a properly functioning fuel pump and system.