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HOMESERVICE MANUALSMAZDA2006B4000 BASE, AUTOMATICREPAIR AND DIAGNOSIS (SINGLE PAGE)ENGINE PERFORMANCETESTING & DIAGNOSISENGINE SYMPTOM TROUBLESHOOTING - (3 OF 5)DTC APPLICATION CHART - POWERTRAIN CONTROL MODULE (PCM)DATA LINK CONNECTOR (DLC) MALFUNCTION

2006 Mazda B4000 Base, Automatic

Data Link Connector (DLC) Malfunction

2006 Mazda B4000 Base, AutomaticSECTION Data Link Connector (DLC) Malfunction

DTC P1001 OR DTC NOT LISTED DETECTION CONDITION & POSSIBLE CAUSES

DTC P1001 OR DTC NOT LISTED	DATA LINK CONNECTOR (DLC) MALFUNCTION
DETECTION CONDITION	P1001 indicates any of the following. Unable to access continuous memory DTCs Unable to activate KOEO or KOER Self Test WDS or equivalent tester communication problem DTC displayed by WDS or equivalent tester not listed KOER Self Test cannot be completed
POSSIBLE CAUSE	Damaged DLC Incorrect self-test procedure VREF is not in specification Idle RPM out of specification Open in DLC harness circuit Short in DLC circuit or associated modules Damaged powertrain control module (PCM) power relay circuit Damaged PCM
Courtesy of MAZDA MOTORS CORP.
Courtesy of MAZDA MOTORS CORP.
Courtesy of MAZDA MOTORS CORP.

DTC P1001 DIAGNOSTIC PROCEDURE

DTC P1001 OR DTC NOT LISTED		DATA LINK CONNECTOR (DLC) MALFUNCTION
STEP	INSPECTION		ACTION
1	Was the PCM quick test performed?	Yes	Go to next step.
1	Was the PCM quick test performed?	No	Perform PCM quick test. See PCM QUICK TEST .
2	CHECK FOR VREF AT TP SENSOR Key OFF. Disconnect throttle position (TP) sensor. Key on, engine off (KOEO). Measure voltage between VREF and SIG RTN TP sensor harness connector. Key OFF. Are the voltage between 4.0 and 6.0 V?	Yes	Voltage is within specification. Connect TP sensor. Go to next step.
2		No	Voltage is not within specification. Connect TP sensor. See GENERAL PINPOINT TEST 1: VEHICLE REFERENCE VOLTAGE .
3	ABILITY TO ACCESS CONTINUOUS MEMORY DTCs Can continuous memory DTCs be accessed?	Yes	Go to next step.
3		No	Unable to access continuous memory DTCs. Go to step 7.
4	ABILITY TO ACTIVATE KOEO SELF-TEST Can KOEO self-test be activated?	Yes	Go to next step.
4		No	Unable to activate KOEO self-test. Go to step 6.
5	ABILITY TO ACTIVATE KOER SELF-TEST Can KOER self-test be activated?	Yes	If here for DTC P1001 and other KOER DTCs are present, begin diagnosis with the first KOER DTC that appears. If DTC is not listed in the charts, verify that correct PCM is installed on vehicle.
5		No	Go to next step.
6	RETRIEVE ANY CONTINUOUS MEMORY DTCs NOTE: If failures are present in the following components or systems, the EEC strategy can be prevented from completing the KOER self-test or cause the PCM to generate a WDS or equivalent tester communication error message: Idle speed control EGR system Fuel control system Vehicle speed signal circuits Mass air flow sensor circuits Transmission range circuits Key on, engine off (KOEO). Retrieve and record continuous memory DTCs (MIL and non-MIL). Key OFF. Are any continuous memory DTCs present?	Yes	If here for DTC P1001 and other DTCs are present, begin diagnosis with the other DTCs.
6		No	Unable to retrieve any self-test DTCs. Go to next step.
7	CHECK B AT DATA LINK CONNECTOR (DLC) Inspect DLC for damage. Repair as necessary. Measure the voltage between B at DLC and engine block ground. Is voltage greater than 10.5 V?	Yes	Go to next step.
7		No	Repair open in data link connector B+ circuit. Go to step 16.
8	CHECK DLC CHASSIS GROUND RESISTANCE Measure resistance between chassis ground at DLC and chassis ground. Is resistance less than 5.0 ohms?	Yes	Go to next step.
8		No	Repair open in DLC chassis ground circuit. Go to step 16.
9	CHECK DLC PWR GND CIRCUIT FOR OPEN IN HARNESS Measure resistance between PWR GND at the DLC and battery negative post. Is resistance less than 5.0 ohms?	Yes	Data link passed. Go to next step.
9		No	Repair open circuit. Go to step 16.
10	CHECK BUS FOR SHORT TO GROUND IN HARNESS Disconnect PCM. Install breakout box, leave PCM disconnected. Measure resistance of BUS circuit between PCM test pin 16 and chassis ground. Is resistance greater than 50 ohms?	Yes	Go to next step.
10		No	Repair short circuit. NOTE: Short circuit can exist in harness or associated modules. See SYMPTOM TROUBLESHOOTING CHART - COMMUNICATIONS NETWORK for further diagnosis.
11	CHECK BUS CIRCUIT FOR SHORT TO B IN HARNESS Key on engine off (KOEO). Measure voltage between BUS circuit at the PCM harness connector pin 16 (T/O) of connector 0140-175 and chassis ground. Is the voltage greater than 1.0 volt?	Yes	Repair short circuit. NOTE: Short circuit can exist in harness or associated modules. See SYMPTOM TROUBLESHOOTING CHART - COMMUNICATIONS NETWORK for further diagnosis.
11		No	Go to next step.
12	CHECK DLC BUS+ CIRCUIT FOR OPEN IN HARNESS Key OFF. Measure resistance of BUS+ circuit between PCM test pin 16 and pin 2 of the DLC connector. Is resistance greater than 5.0 ohms?	Yes	Go to next step.
12		No	Repair open circuit. Go to step 16.
13	CHECK BUS- FOR SHORT TO GROUND IN HARNESS Key OFF. Measure resistance of BUS- circuit between PCM test pin 15 and chassis ground. Is resistance greater than 50 ohms?	Yes	Go to next step.
13		No	Repair short circuit. NOTE: Short circuit can exist in harness or associated modules. See SYMPTOM TROUBLESHOOTING CHART - COMMUNICATIONS NETWORK for further diagnosis.
14	CHECK BUS- CIRCUIT FOR SHORT TO B+ IN HARNESS Key ON, Engine OFF (KOEO). Measure voltage between BUS- circuit between PCM test pin 15 and chassis ground. Is the voltage greater than 6.0 V?	Yes	Repair short circuit. NOTE: Short circuit can exist in harness or associated modules. See SYMPTOM TROUBLESHOOTING CHART - COMMUNICATIONS NETWORK for further diagnosis.
14		No	Go to next step.
15	CHECK DLC BUS- CIRCUIT FOR OPEN IN HARNESS Key OFF. Measure resistance of BUS- circuit between PCM test pin 15 and pin 10 of the DLC connector. Is resistance less than 5.0 ohms?	Yes	Replace PCM. See POWERTRAIN CONTROL MODULE (PCM) REMOVAL / INSTALLATION . Go to next step.
15		No	Repair open circuit. Go to next step.
16	VERIFY TROUBLESHOOTING OF DTCs COMPLETED Connect all disconnected connectors. Clear DTCs from PCM memory using WDS or equivalent tester. Perform PCM quick test. Is same DTC present?	Yes	Replace PCM. See POWERTRAIN CONTROL MODULE (PCM) REMOVAL / INSTALLATION . Repeat PCM quick test.
16		No	If any other DTC is present, Go to applicable DTC inspection. See DIAGNOSTIC TROUBLE CODE (DTC) INDEX - POWERTRAIN CONTROL MODULE (PCM) . If no DTC is present, troubleshooting is complete.

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

• You smell fuel, burning insulation, or see smoke.
• Brakes feel soft, pull hard to one side, or make grinding noises.
• The engine overheats, stalls repeatedly, or misfires under load.
• You are missing required tools, torque specs, or safe lifting equipment.
• You are not confident in the next step or safety outcome.