DTC P2503 [LF]

2008 - MX-5 - Engine

DTC P2503 [LF]


DTC P2503	Charging system voltage low
DETECTION CONDITION	PCM needs more than 20 A from generator, and judges generator output voltage to be below 8.5 V during engine running. Diagnostic support note This is a continuous monitor (Other). The MIL does not illuminate. PENDING CODE is available if the PCM detects the above malfunction condition during the first drive cycle. FREEZE FRAME DATA is available. The DTC is stored in the PCM memory.
POSSIBLE CAUSE	Generator malfunction PCM and/or generator are poorly connected Open and/or short to ground in wiring from between generator terminal P and PCM terminal 2AJ Open and/or short to ground in wiring from between generator terminal D and PCM terminal 2AI Drive belt misadjustment

Diagnostic procedure


STEP	INSPECTION		ACTION
1	VERIFY FREEZE FRAME DATA HAS BEEN RECORDED Has FREEZE FRAME DATA been recorded?	Yes	Go to the next step.
1		No	Record the FREEZE FRAME DATA on the repair order, then go to the next step.
2	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.
2		No	Go to the next step.
3	INSPECT DRIVE BELT CONDITION Verify that drive belt auto tensioner indicator mark does not exceed limit. Is drive belt normal?	Yes	Go to the next step.
3		No	Replace and/or adjust drive belt, then go to Step 10.
4	INSPECT POOR CONNECTION OF PCM CONNECTOR Turn the ignition switch off. Disconnect PCM connector. Inspect for poor connection (damaged, pulled-out terminals, corrosion, etc.). Is there any malfunction?	Yes	Repair the terminals, then go to Step 10.
4		No	Go to the next step.
5	INSPECT POOR CONNECTION OF GENERATOR CONNECTOR Disconnect generator connector. Inspect for poor connection (damaged, pulled-out terminals, corrosion, etc.). Is there any malfunction?	Yes	Repair or replace the terminals, then go to Step 10.
5		No	Go to the next step.
6	INSPECT GENERATOR CONTROL CIRCUIT FOR SHORT TO GROUND Inspect for continuity between generator terminal D (wiring harness-side) and body ground. Is there continuity?	Yes	Repair or replace the wiring harness for short to ground, then go to Step 10.
6		No	Go to the next step.
7	INSPECT GENERATOR OUTPUT VOLTAGE MONITOR CIRCUIT FOR SHORT TO GROUND Inspect for continuity between generator terminal P (wiring harness-side) and body ground. Is there continuity?	Yes	Repair or replace the wiring harness for short to ground, then go to Step 10.
7		No	Go to the next step.
8	INSPECT GENERATOR CONTROL CIRCUIT FOR OPEN Inspect for continuity between generator terminal D (wiring harness-side) and PCM terminal 2AI (wiring harness-side). Is there continuity?	Yes	Go to the next step.
8		No	Repair or replace the wiring harness for open circuit, then go to Step 10.
9	INSPECT GENERATOR OUTPUT VOLTAGE MONITOR CIRCUIT FOR OPEN CIRCUIT Inspect for continuity between generator terminal P (wiring harness-side) and PCM terminal 2AJ (wiring harness-side). Is there continuity?	Yes	Repair or replace the generator, then go to the next step.
9		No	Repair or replace the wiring harness for open circuit, then go to the next step.
10	VERIFY TROUBLESHOOTING OF DTC P2503 COMPLETED Make sure to reconnect all connectors. Clear the DTC from the PCM memory using the M-MDS. Start the engine, or perform the KOER self-test with M-MDS. (See KOEO/KOER SELF TEST [LF].) Is the same DTC present?	Yes	Replace the PCM, then go to the next step. (See PCM REMOVAL/INSTALLATION [LF].)
10		No	Go to the next step.
11	VERIFY AFTER REPAIR PROCEDURE Perform “AFTER REPAIR PROCEDURE”. (See AFTER REPAIR PROCEDURE [LF].) Is any DTC present?	Yes	Go to the applicable DTC inspection. (See DTC TABLE [LF].)
11		No	Troubleshooting completed.

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