DTC P0562 System Voltage Low. GMC Truck Sonoma Pickup

For 1990-2009 cars only

Makes 🢒 GMC_Truck 🢒 1997 🢒 Sonoma Pickup - 4WD 🢒 DTC 🢒 DTC P0562 System Voltage Low

Engine Controls Components
Power, Ground, MIL
OBD II Symbol Description Notice
Engine Controls Connector End Views
Handling ESD Sensitive Parts Notice

Circuit Description

The Powertrain Control Module (PCM) monitors the system voltage on the ignition feed terminals to the PCM. A system voltage DTC sets whenever the voltage is below a calibrated value.

Conditions For Setting The DTC

•	The system voltage is less than 10 V.

•	The RPM is greater than 1300 RPM.

•	The fault is present for 240 seconds.

Action Taken When the DTC Sets

•	The PCM records the operating conditions at the time the diagnostic fails. The Failure Records buffers stores this information.

•	A history DTC is stored.

Conditions for Clearing the DTC

•	A History DTC clears after 40 consecutive warm up cycles without a fault.

•	Use a scan tool to clear the DTCs.

Diagnostic Aids

Whenever a DTC sets when an accessory is operated, check for a poor connection or an excessive current draw.

Test Description

Number(s) below refer to the step number(s) on the Diagnostic Table.

The Powertrain OBD System Check prompts the technician to complete some basic checks and store the freeze frame and failure records data on the scan tool if applicable. This creates an electronic copy of the data taken when the malfunction occurred. The information is then stored on the scan tool for later reference.

This checks if the generator is malfunctioning under load conditions.

PCM Controlled Generator Diagnosis will further check the PCMs control of the generator.

Checks ignition positive voltagecircuit #2 for excessive resistance. An open circuit will cause a no start condition.

Replacement PCMs must be reprogrammed and the crankshaft position system variation procedure must be performed. Refer to the latest Techline information for PCM reprogramming and also refer to the Powertrain Control Module (PCM) for the Crankshaft Position System Variation Procedure.

If no malfunctions have been found at this point and no additional DTCs were set, refer to Diagnostic Aids for additional checks and information.

DTC P0562-System Voltage Low

Step	Action	Value(s)	Yes	No
1	Was the Powertrain On-Board Diagnostic (OBD) System Check performed?	--	Go to Step 2	Go to Powertrain On Board Diagnostic (OBD) System Check
2	Install a scan tool. Start the engine and raise the engine speed to the specified value. Load the electrical system by turning on the headlights, high blower motor, etc. Is the ignition voltage less than the specified value?	1400 RPM 10 V	Go to Step 3	Go to Step 8
3	With the engine still running at the specified value. Using a DVM, measure the battery voltage at the battery. Is the battery voltage greater than the specified value?	1400 RPM 12V	Go to Step 4	Go to PCM Controlled Generator Diagnosis
4	Turn the ignition switch OFF. Disconnect the PCM connector at the PCM. Turn the ignition switch ON, with the engine OFF. Using a DVM, measure the ignition voltage at the ignition positive voltage circuit #2. Is the ignition voltage greater than the specified value?	10V	Go to Step 5	Go to Step 6
5	Check for a malfunctioning connection at the PCM harness terminals and repair as necessary. Was a repair necessary?	--	Go to Step 8	Go to Step 7
6	Repair the poor connection (high resistance) in the ignition positive voltage circuit #2. Is the action complete?	--	Go to Step 8	--
7	Replace the PCM. Is the action complete?	--	Go to Step 8	--
8	Using the scan tool, clear the DTCs. Start the engine and idle at normal operating temperature. Operate the vehicle within the conditions for setting this DTC as specified in the supporting text. Does the scan tool indicate that this diagnostic has ran and passed?	--	Go to Step 9	Go to Step 2
9	Check if any additional DTCs set. Are any DTCs displayed that have not been diagnosed?	--	Go to applicable DTC table	System OK Refer to Diagnostic Aids