DTC P0A94:00 [SKYACTIV-G 2.5]

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2014 - Mazda6 - Engine

DTC P0A94:00 [SKYACTIV-G 2.5]

NOTE:

To determine the malfunctioning part, proceed with the diagnostics from “Function Inspection Using M-MDS”.

Details On DTCs


DESCRIPTION	DC-DC converter: control circuit signal error
DETECTION CONDITION	Determination conditions	Internal malfunction signal from DC-DC converter is received. Condition in which DC-DC converter output voltage, based on demand voltage of PCM, is low continues. When PCM outputs drive command signal for each type of relay in DC-DC converter, relay condition signal returned from DC-DC converter differs from drive command, or not returned
	Preconditions	Not applicable
	Drive cycle	1
	Self test type	CMDTC self test
	Sensor used	Not applicable
FAIL-SAFE FUNCTION	The following fail-safe differ depending on the type of malfunction Transition to i-ELOOP bypass mode. i-ELOOP bypass mode inhibited.
VEHICLE STATUS WHEN DTCs ARE OUTPUT	The following vehicle conditions differ depending on the type of malfunction Illuminates the master warning light The pre-charge mode is implemented after the engine is started.
POSSIBLE CAUSE	Connector or terminal malfunction of the following parts: PCM Battery DC-DC converter Short to ground in wiring harness between the following terminals: DC-DC converter terminal 1G—PCM terminal 2W DC-DC converter terminal 1I—PCM terminal 2L Open circuit in wiring harness between the following terminals: DC-DC converter terminal 1G—PCM terminal 2W DC-DC converter terminal 1I—PCM terminal 2L DC-DC converter malfunction (DTC U3000:49 may be detected simultaneously) PCM malfunction

System Wiring Diagram

Function Explanation (DTC Detection Outline)

With the DC-DC converter function, the PCM performs malfunction determination, and verification of vehicle malfunctions/safety assurance is performed.

The DC-DC converter is equipped with a voltage lowering function which supplies power to the 12 V line from the 25 V line. If this function does not operate, it may not be possible to supply power to the vehicle’s electrical devices. In this diagnostic, the system detects whether the DC-DC converter can respond to the command voltage from the PCM, or it detects a malfunction in the voltage lowering circuit based on the on-board diagnostic of the DC-DC converter.

The DC-DC converter is equipped with a discharge circuit which discharges a certain amount of capacitor (i-ELOOP) voltage when the ignition is switched off. If this function does not operate, the capacitor (i-ELOOP) may deteriorate. In this diagnostic, a discharge circuit malfunction condition is detected in the DC-DC converter, and a malfunction is determined by the PCM.

The DC-DC converter is equipped with a bypass circuit which supplies voltage generated by the generator to the 12 V line. If this function does not operate, a power supply shortage may occur. In this diagnostic, a bypass circuit malfunction condition is detected in the DC-DC converter, and a malfunction is determined by the PCM. In addition, a malfunction is determined by the PCM from a mismatch with the response signal of the DC-DC converter in relation to the bypass relay drive command signal from the PCM.

The DC-DC converter monitors the input/output voltage and the output current, and the PCM performs charge/discharge control of the generator based on each of the signals to assure the vehicle’s power supply. If the output current of the DC-DC converter exceeds the assurance value of the internal circuit, or each input/output value indicates an abnormal value, normal supply of electricity may not be possible. In this diagnostic, each input/output terminal of the DC-DC converter is detected as an abnormal value/exceeding assurance value, and a malfunction is determined by the PCM.

Repeatability Verification Procedure

Clear the DTC from the PCM memory using the M-MDS. (See CLEARING DTC [SKYACTIV-G 2.5].)

Start the engine.

Leave for 30 s while idling with no electrical load.

Leave for 30 s while idling with high electrical load.

PID Item/Simulation Item Used In Diagnosis

Not applicable

Function Inspection Using M-MDS


STEP	INSPECTION	RESULTS	ACTION
1	VERIFY RELATED REPAIR INFORMATION AVAILABILITY Verify related Service Bulletins and/or on-line repair information availability. Is any related repair information available?	Yes	Perform repair or diagnosis according to the available repair information. If the vehicle is not repaired, go to the next step.
1		No	Go to the next step.
2	PURPOSE: VERIFY IF POWER SUPPLY IS AFFECTED BY DTC RELATED TO DC-DC CONVERTER Switch the ignition off, then ON (engine off). Perform the DC-DC converter DTC inspection using the M-MDS. (See DTC INSPECTION [i-ELOOP].) Is the PENDING CODE/DTC U3000:49 also present?	Yes	Go to the applicable PENDING CODE or DTC inspection. (See DTC U3000:49 [i-ELOOP].) Go to the next step.
2		No	Go to the next step.
3	PURPOSE: VERIFY IF POWER SUPPLY IS AFFECTED BY DTC RELATED TO PCM Perform the Pending Trouble Code Access Procedure and DTC Reading Procedure. (See ON-BOARD DIAGNOSTIC TEST [SKYACTIV-G 2.5].) Is the PENDING CODE/DTC P0A12:00 also present?	Yes	Go to the applicable PENDING CODE or DTC inspection. (See DTC P0A12:00 [SKYACTIV-G 2.5].) Go to the next step.
3		No	Go to the next step.
4	PURPOSE: DETERMINE IF MALFUNCTION CAUSED BY DC-DC CONVERTER Start the engine. Is illuminate the master warning light?	Yes	Go to the troubleshooting procedure to perform the procedure from Step 1.
4		No	Go to the troubleshooting procedure to perform the procedure from Step 3.

Troubleshooting Diagnostic Procedure

Intention of troubleshooting procedure

Step 1—2

Verifying malfunction related to DC-DC converter 1G or 1I terminal

Step 3—4

Verifying/replacing malfunctioning part

Step 5—6

Verify that primary malfunction is resolved and there are no other malfunctions.


STEP	INSPECTION	RESULTS	ACTION
1	PURPOSE: VERIFY IF SHORT TO GROUND IN EACH WIRING HARNESS AFFECTS DIAGNOSTIC RESULTS Switch the ignition off. Disconnect the service plug. (See SERVICE PLUG DISCONNECTION/CONNECTION [i-ELOOP].) Disconnect the connector of the following parts. PCM DC-DC converter Inspect for continuity between the following terminals (wiring harness-side) and body ground: DC-DC converter terminal 1G DC-DC converter terminal 1I Is there continuity?	Yes	Refer to the wiring diagram and verify whether or not there is a common connector between the following terminals: PCM terminal 2W—DC-DC converter terminal 1G PCM terminal 2L—DC-DC converter terminal 1I If there is a common connector: Determine the malfunctioning part by inspecting the common connector and the terminal for corrosion, damage, or pin disconnection, and the common wiring harness for a short to ground. Repair or replace the malfunctioning part. If there is no common connector: Repair or replace the wiring harness which has a short to ground. Go to Step 5.
1		No	Go to the next step.
2	PURPOSE: VERIFY IF OPEN CIRCUIT IN EACH WIRING HARNESS AFFECTS DIAGNOSTIC RESULTS Verify that the DC-DC converter and PCM connectors are disconnected. Inspect for continuity between the following terminals (wiring harness-side): PCM terminal 2W—DC-DC converter terminal 1G PCM terminal 2L—DC-DC converter terminal 1I Is there continuity?	Yes	Replace the DC-DC converter. (See DC-DC CONVERTER REMOVAL/INSTALLATION [i-ELOOP].) Go to Step 5.
2		No	Refer to the wiring diagram and verify whether or not there is a common connector between the following terminals: PCM terminal 2W—DC-DC converter terminal 1G PCM terminal 2L—DC-DC converter terminal 1I If there is a common connector: Determine the malfunctioning part by inspecting the common connector and the terminal for corrosion, damage, or pin disconnection, and the common wiring harness for an open circuit. Repair or replace the malfunctioning part. If there is no common connector: Repair or replace the wiring harness which has an open circuit. Go to Step 5.
3	PURPOSE: VERIFY IF MALFUNCTION OCCURRING IS CAUSED BY WIRING HARNESS/CONNECTOR LOSS Have all the wiring harnesses/connectors which can be considered the cause of DTC P0A94:00 been inspected?	Yes	Go to the next step.
3		No	Inspect all the related wiring harnesses/connectors. If there is a malfunction Repair or replace the connector and/or terminals, then go to Step 5. If there is no malfunction Go to the next step.
4	PURPOSE: VERIFY DC-DC CONVERTER REPLACEMENT RECORD Is the DC-DC converter being replaced within the troubleshooting diagnostic procedure this time?	Yes	Replace the PCM. (See PCM REMOVAL/INSTALLATION [SKYACTIV-G 2.5].) Go to the next step.
4		No	Replace the DC-DC converter. (See DC-DC CONVERTER REMOVAL/INSTALLATION [i-ELOOP].) Go to the next step.
5	PURPOSE: VERIFICATION OF VEHICLE REPAIR COMPLETION Always reconnect all disconnected connectors. Reconnect the service plug. (See SERVICE PLUG DISCONNECTION/CONNECTION [i-ELOOP].) Clear the DTC from the PCM memory using the M-MDS. (See CLEARING DTC [SKYACTIV-G 2.5].) Implement the repeatability verification procedure. (See Repeatability Verification Procedure.) Perform the DTC Reading Procedure. (See ON-BOARD DIAGNOSTIC TEST [SKYACTIV-G 2.5].) Is the same DTC present?	Yes	Repeat the inspection from Step 3.
5		No	Go to the next step.
6	PURPOSE: VERIFY IF THERE IS ANY OTHER MALFUNCTION Is any other DTC or pending code stored?	Yes	Go to the applicable DTC inspection. (See DTC TABLE [SKYACTIV-G 2.5].)
6		No	DTC troubleshooting completed.

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