P0562: P0562 Diagnostic Guide

What this code means

P0562 generally means the PCM may be seeing system voltage lower than the charging voltage it expects.

What the vehicle may do

The vehicle may have a low or discharged battery complaint.
The charging warning indicator may come on.
Electrical behavior may be intermittent or weak when demand is high.
Starting concerns can occur if the battery is not being maintained.

Possible fault areas

Possible battery or battery connection concerns.
Possible generator output or B+ circuit concerns.
Possible engine, generator, or battery ground concerns.
Possible PCM or BCM power and ground circuit concerns.
Possible loose, corroded, damaged, or backed-out connector terminals.

Diagnostic path

Opening context

On this 6.2 gas Super Duty, P0562 means the PCM is seeing system voltage lower than the generator voltage it wants. In plain terms, the charging system may not be keeping up with demand, or the modules may be seeing the wrong voltage because of resistance in power or ground circuits. The truck may have a low battery, charging complaints, warning indicators, or intermittent electrical behavior. Broadly, this can involve the battery and connections, the generator B+ side, grounds, PCM power and ground circuits, BCM supply and ground circuits, or connector problems. For this code, the PCM sets P0562 when voltage drops 1.5 volts or more below the generator voltage desired, as calculated by the PCM, after 30 seconds.

Pre-checks before testing

Before starting the low-voltage pinpoint path, do the basic inspection work. Inspect the battery and the front-end accessory drive. Check the high-current BJB fuse F201, 275A MEGA, and BJB position number 58, fuse 45, 10A. Look over the BJB and high-current BJB connections for anything loose, damaged, or corroded. Battery voltage needs to be greater than 12.2 volts before and during this test, and do not leave a battery charger connected while testing the vehicle.

Initial inspection and code context

Start with the basic system checks. If you find an obvious cause for the customer concern, correct that first. If nothing obvious turns up, run the PCM self-test. If other generator control-related codes are present, follow the appropriate path for those first. If they are not present, continue with the P0562 low-voltage path.

Generator connection and static B+ check

Next, check the generator connections with the ignition off. Disconnect generator C102A and C102B. Inspect for corrosion, damaged or bent pins, pushed-out pins, and loose terminals. If the truck has a radial arm adapter, include that in the inspection, because the B+ terminal at the generator can be serviced separately from the generator. Reconnect the connectors and make sure they fully seat and latch. Measure C102B Pin 1 to ground and compare that reading to the recorded battery voltage. If it is within 0.5 volt of battery voltage, move on. If it is not, correct the B+ connection issue as needed, including the B+ nut or radial arm adapter if equipped, then verify high-current BJB fuse 201, 275A MEGA. If the fuse is good, repair the circuit. If the fuse is not good, identify the cause of the short before moving on.

Generator B+ and ground voltage drop

Now run the engine at idle with the headlamps on and the blower on high. Check voltage drop in the generator B+ circuit at C102B Pin 1, and wiggle the generator wiring and connections while watching the reading. If the drop is less than 0.5 volt, continue. If it is not, inspect and repair corrosion in the B+ circuit and positive battery cable connections, and check the B+ nut and radial arm adapter, if equipped, for looseness. After repairs, clear the DTCs, repeat the self-test, and test the system for normal operation. If B+ voltage drop passes, check vehicle ground voltage drop at the generator case under the same idle, headlamp, and blower load. If ground voltage drop is less than 0.5 volt, continue. If not, inspect and repair corrosion in the engine ground, generator ground, or battery ground.

Commanded generator voltage and PCM voltage comparison

With the basic B+ and ground checks passing, command the generator voltage desired PID. Access the PCM, monitor GENVDSD, command it to 14 volts, and with the engine idling, measure and record battery voltage. If the recorded battery voltage is within ±0.5 volt of the commanded PID, keep going. If it is not, install a new generator. Next, with the engine idling, headlamps on, and blower on high, measure and record battery voltage again. Then monitor the PCM VPWR PID. If VPWR displays battery voltage within ±0.5 volt of the recorded battery voltage, continue into circuit load testing. If it does not, repair high resistance or loose connections in the affected PCM power circuit or circuits.

PCM power and ground load tests

Turn the ignition off, disconnect the BJB PCM power relay, and disconnect PCM C175B. Load test the PCM supply circuits with a headlamp bulb or an effective load, using the proper probe setup so the connector terminals are not damaged. Connect the load to a suitable ground and check the PCM power feeds at C175B Pin 1, Pin 2, and Pin 16 to ground. If the voltages are within 0.5 volt of recorded battery voltage, continue. If not, repair the affected circuit or circuits. The test path then says to remove the fused jumper wire. If that jumper setup is not clear in your workflow, pause, recheck the earlier diagnostic path, and do not guess. Next, load test the PCM grounds using a suitable 12 volt power connection and check the ground circuits at C1232B Pin 46, Pin 47, Pin 61, Pin 62, and Pin 76. If voltage drop is less than 0.5 volt, continue. If not, repair the affected circuit or circuits.

BCM power and ground load tests

Next, compare the BCM voltage supply circuits. With the ignition off, disconnect all BCM connectors. Load test the supply circuits with a headlamp bulb or effective load and the proper connector probe setup. Connect the load to a suitable ground and check C2280G Pin 22, Pin 21, and Pin 17 to ground. If those voltages are within 0.5 volt of recorded battery voltage, continue. If not, repair the affected circuit or circuits. Then load test the BCM grounds using a suitable 12 volt power connection. Check C2280C Pin 6, Pin 7, and Pin 10 to ground. If voltage drop is less than 0.5 volt, go to the dynamic VPWR check. If not, repair the affected circuit or circuits.

Dynamic VPWR check

For the next check, measure battery voltage at the battery. With the engine idling and all accessory loads turned off, measure and record battery voltage, then view and record the PCM VPWR PID. Momentarily accelerate the engine to wide open throttle and release it. Repeat that 4-5 times while watching the PID. If VPWR stays within 0.5 volt of recorded battery voltage as engine RPM increases, the system is operating correctly at this time. Inspect and repair any connector or pin problems you find. If no connector or pin problems are found, perform a battery drain test. If VPWR does not stay within 0.5 volt of recorded battery voltage, continue to the PCM connector inspection.

PCM connector check and repair verification

With the ignition off, disconnect and inspect all PCM connectors. If you find corrosion, repair it by installing the needed connector or terminals and cleaning the module pins. If you find damaged or bent pins, repair them with new terminals or pins. If pins are pushed out, install new pins as necessary. Reconnect everything and make sure every connector seats and latches correctly, then operate the system. If the concern is gone, the system is operating correctly at this time, and the fault may have been caused by a loose or corroded connector. Address the root cause of any connector or pin issue. If the concern is still present, check for any applicable TSB. If one applies, stop this path and follow that TSB. If no TSB applies, continue with the Ford guided PCM routine. After any repair, verify the repair and confirm the code stays gone.

Takeaway

The key on P0562 is not to jump straight to the generator. Prove the B+ path, prove the grounds, compare commanded generator voltage to actual battery voltage, then load test the module power and ground circuits before making the call. For more diagnostic training, visit stepdiagnostics.com.