Engine Controls - Tests W/codes Porsche 911 Carrera 4 996

INTRODUCTION

If no faults were found while performing BASIC TESTING , proceed with self-diagnostics. Also see I - SYSTEM & COMPONENT TESTS article.

SELF-DIAGNOSTIC SYSTEM

If a monitored component malfunctions, Digital Motor Electronics (DME) Electronic Control Module (ECM) stores Diagnostic Trouble Codes (DTCs). DTC, in most cases, is indicated by Malfunction Indicator Light (MIL). ECM is located under driver's seat. DTCs can be read using Porsche System Tester 2 or generic scan tool connected to Data Link Connector (DLC). DLC is located under left side of instrument panel, on side of console. (Scheme 2)

MALFUNCTION INDICATOR LIGHT (MIL)

MIL (or CHECK ENGINE light) comes on if most DTCs are set. See DTC DEFINITION . MIL comes on as a self-test when ignition switch is in ON position. After engine starts, MIL goes out to indicate no DTCs are present. If MIL remains on, a fault is present.

Scheme 2

RETRIEVING & CLEARING DIAGNOSTIC TROUBLE CODES (DTC)

Diagnostic Trouble Codes (DTCs) are retrieved and cleared using a scan tool connected to Data Link Connector (DLC). DLC is located under left side of instrument panel, on side of console. (Scheme 2) Follow scan tool manufacturer's instructions for retrieving and erasing DTCs. See DTC DEFINITION.

DTC DEFINITION

Scheme 3

* PLEASE READ FIRST *

Note. Ensure ignition is off when taking resistance measurements. ECM is located under driver's seat. For ECM connector terminal identification, see illustration. (Scheme 3)

Scheme 4

DTC P0101, P0102 & P0103: MAF SENSOR SIGNAL

If DTC P0101 is present, replace MAF sensor. If DTC P0102 is present, check Blue/Green wire between MAF sensor terminal No. 2 and ECM terminal No. 17 for an open circuit or short to ground. If DTC P0103 is present, check Blue/Green wire between MAF sensor and ECM for a short to voltage. Repair as necessary.

DTC P0112 & P0113: IAT SENSOR

1. Disconnect IAT sensor connector. Connect ohmmeter between IAT sensor connector terminals No. 1 and 2. If resistance is 2.3-2.7 k/ohms, go to next step. If resistance is not 2.3-2.7 k/ohms, replace IAT sensor.
2. Check Green/Blue wire between IAT sensor terminal No. 1 and ECM terminal No. 16 for an open circuit or short to ground (P0112), or short to voltage (P0113). Repair as necessary.

DTC P0115 & P0117: ENGINE TEMPERATURE SENSOR

Check resistance at engine temperature sensor. See ENGINE TEMPERATURE SENSOR SPECIFICATION . If resistance is not to specification, replace engine temperature sensor. If resistance is to specification, check wiring between engine temperature sensor and ECM for an open circuit, short to ground, or short to voltage. Repair as necessary.

ENGINE TEMPERATURE SENSOR SPECIFICATION

DTC P0122 & P0123: THROTTLE POSITION (TP) SENSOR

1. Disconnect TP sensor connector and connect Adapter Cable (VAG 1501). Turn ignition on. Connect voltmeter between TP sensor connector terminal No. 1 (White wire) and No. 2 (Brown wire). About 5 volts should be present. Connect voltmeter between terminals No. 1 (White wire) and No. 3 (White/Green wire). At closed throttle about 4.5 volts should be present. At wide open throttle about .5 volts should be present. If voltages are to specification, go to next step. If voltages are not to specification, go to step 3).
2. Turn ignition off. Disconnect TP sensor connector. Connect ohmmeter between TP sensor terminals No. 1 and 2. About 1.6-2.4 k/ohms should be present. Connect ohmmeter between TP sensor terminals No. 2 and 3. About 710-1380 ohms should be present. If resistances are to specification, problem is intermittent. If resistances are not to specification, replace TP sensor.
3. Ensure ignition is off. Disconnect TP sensor and ECM connectors. Ensure continuity is present in White wire between TP sensor terminal No. 1 and ECM connector terminal No. 53, Brown wire between TP sensor terminal No. 2 and ECM connector terminal No. 34, and White/Green wire between TP sensor connector terminal No. 3 and ECM connector terminal No. 44. Repair wiring as necessary. If continuity is present, go to next step.
4. Reconnect ECM connector. Turn ignition on. Connect voltmeter between TP sensor connector terminal No. 1 (White wire) and ground. About 5 volts should be present. Connect voltmeter between TP sensor connector terminal No. 2 (Brown wire) and ground, then between TP sensor connector terminal No. 3 (White/Green wire) and ground. No voltage should be present. Connect voltmeter between TP sensor connector terminal No. 1 (White wire) and voltage. No voltage should be present. Connect voltmeter between TP sensor connector terminal No. 3 (Yellow/Black wire) and voltage. About 6 volts should be present. Repair wiring as necessary.

DTC P0130: HO2S AHEAD OF TWC

1. Run engine to heat HO2S No. 1 ahead of TWC. Connect scan tool and read HO2S voltage. If voltage fluctuates between 100-800 millivolts, go to next step. If voltage does not fluctuate between 100-800 millivolts, disconnect HO2S connector. Connect voltmeter between HO2S connector terminals No. 3 (Brown wire) and No. 4 (White wire). If 450 millivolts are present, replace HO2S. If no voltage is present, go to next step.
2. Disconnect HO2S and ECM connectors. (Scheme 5)and (Scheme 6). Measure resistance between ECM connector terminal No. 19 (White wire) and HO2S connector terminal No. 4. If no continuity is present, replace wiring harness. If continuity is present, disconnect all HO2S connectors. Measure resistance between ECM connector terminal No. 46 (Brown wire) and HO2S connector terminal No. 3. If continuity is present, go to next step. If continuity is not present, repair open circuit in wiring.
3. Reconnect ECM connector. Connect voltmeter between HO2S connector terminals No. 3 (Brown wire) and No. 4 (White wire). Turn ignition on. If 450 millivolts are present, problem is intermittent. If 450 millivolts are not present, replace ECM.

Scheme 5

Scheme 6

DTC P0131: HO2S AHEAD OF TWC

1. Disconnect all 4 HO2S connectors. (Scheme 5)and (Scheme 6). Turn ignition on. Connect voltmeter between HO2S No. 1 connector ahead of TWC terminals No. 3 (Brown wire) and No. 4 (White wire). About 450 millivolts should be present. Connect voltmeter between terminal No. 3 (Brown wire) and ground. About 720 millivolts should be present. If voltages are to specification, go to next step. If voltages are not to specification, check wiring for a short circuit to ground. If wiring is okay, replace ECM. 2) Connect ohmmeter between HO2S terminals. See «DTC P0131 HO2S RESISTANCE CHECK»(/porsche/911-carrera-4/996-1997-2000/remont/testing-diagnostics/#engine-controls-tests-wcodes). Resistance should be infinite. If resistance is to specification, problem is intermittent. If resistance is not to specification, replace HO2S.

DTC P0131 HO2S RESISTANCE CHECK

DTC P0132: HO2S AHEAD OF TWC, SHORT TO VOLTAGE

1. Disconnect all 4 HO2S connectors. (Scheme 5)and (Scheme 6). Turn ignition on. Connect voltmeter between HO2S No. 1 connector ahead of TWC terminals No. 3 (Brown wire) and No. 4 (White wire). About 450 millivolts should be present. Connect voltmeter between terminal No. 3 and ground. About 720 millivolts should be present. If voltages are to specification, go to next step. If voltages are not to specification, check wiring for a short circuit to ground. If wiring is okay, replace ECM.
2. Connect ohmmeter between HO2S terminals. See «DTC P0132 HO2S RESISTANCE CHECK»(/porsche/911-carrera-4/996-1997-2000/remont/testing-diagnostics/#engine-controls-tests-wcodes). If no continuity is present, problem is intermittent. If continuity is present, replace HO2S.

DTC P0132 HO2S RESISTANCE CHECK

DTC P0133 & P0153: HO2S AHEAD OF TWC

Using scan tool, check DTC memory. If other DTCs are present, repair those DTCs first. If DTCs P0133 and/or P0153 are stored, erase DTCs then road test vehicle. It DTCs reoccur, replace HO2S.

DTC P0134: HO2S AHEAD OF TWC INTERMITTENT SIGNAL INTERRUPTION, (CYLS. 1-3)

1. Disconnect all 4 HO2S connectors. (Scheme 5)and (Scheme 6). Turn ignition on. Connect voltmeter between HO2S No. 1 connector ahead of TWC terminals No. 3 (Brown wire) and No. 4 (White wire). About 450 millivolts should be present. Connect voltmeter between terminal No. 3 (Brown wire) and ground. About 720 millivolts should be present. Start and run engine at high speed for 3 minutes. Connect voltmeter between HO2S connector terminals No. 1 (Red/White wire) and No. 2 (Brown wire). Battery voltage should be present. If voltages are to specification, go to next step. If voltages are not to specification, check wiring for a short circuit to ground. If wiring is okay, replace ECM.
2. Reconnect HO2S connectors. Run engine at high engine speed to heat HO2S. Using scan tool, read HO2S voltage. If voltage fluctuates between 100-800 millivolts, go to next step. If voltage does not fluctuate between 100-800 millivolts, replace HO2S.
3. Disconnect HO2S No. 1 connector ahead of TWC. Connect ohmmeter between HO2S terminals No. 1 (Red/White wire) and No. 2 (Brown wire). Resistance should be 1.8-2.5 ohms at 68°F (20°C). Connect ohmmeter between HO2S terminal No. 1 and ground, then between terminal No. 2 and ground. If no continuity is present, HO2S is okay. If continuity is present, replace HO2S.

DTC P0136: HO2S AFTER TWC SHORT CIRCUIT (CYLS. 1-3)

1. Disconnect all 4 HO2S connectors. (Scheme 5)and (Scheme 6). Turn ignition on. Connect voltmeter between HO2S No. 1 connector ahead of TWC terminals No. 3 (Brown wire) and No. 4 (White wire). About 450 millivolts should be present. Connect voltmeter between terminal No. 3 (Brown wire) and ground. About 720 millivolts should be present. If voltages are to specification, go to next step. If voltages are not to specification, check wiring for a short circuit to ground. If wiring is okay, replace ECM.
2. Reconnect HO2S connectors. Run engine at high engine speed to heat HO2S. Sharply depress accelerator several times. Using scan tool, read HO2S voltage. If voltage fluctuates between 100-800 millivolts, HO2S is okay. If voltage does not fluctuate between 100-800 millivolts, replace HO2S.

DTC P0137: HO2S AFTER TWC SHORT TO GROUND (CYLS. 1-3)

1. Disconnect all 4 HO2S connectors. (Scheme 5)and (Scheme 6). Turn ignition on. Connect voltmeter between HO2S No. 1 connector behind TWC terminals No. 3 (Brown wire) and No. 4 (White wire). About 450 millivolts should be present. Connect voltmeter between HO2S connector terminal No. 3 (Brown wire) and ground. About 720 millivolts should be present. If voltages are to specification, go to next step. If voltages are not to specification, check wiring for a short circuit to ground. If wiring is okay, replace ECM.
2. Connect ohmmeter between HO2S terminals. See «DTC P0137 HO2S RESISTANCE CHECK»(/porsche/911-carrera-4/996-1997-2000/remont/testing-diagnostics/#engine-controls-tests-wcodes). If no continuity is present, problem is intermittent. If continuity is present, replace HO2S.

DTC P0137 HO2S RESISTANCE CHECK

DTC P0138: HO2S AFTER TWC SHORT TO VOLTAGE (CYLS. 1-3)

1. Disconnect all 4 HO2S connectors. (Scheme 5)and (Scheme 6). Turn ignition on. Connect voltmeter between HO2S No. 1 connector behind TWC terminals No. 3 (Brown wire) and No. 4 (White wire). About 450 millivolts should be present. Connect voltmeter between terminal No. 3 (Brown wire) and ground. About 720 millivolts should be present. If voltages are to specification, go to next step. If voltages are not to specification, check wiring for a short circuit to voltage. If wiring is okay, replace ECM.
2. Connect ohmmeter between HO2S terminals. See «DTC P0138 HO2S RESISTANCE CHECK»(/porsche/911-carrera-4/996-1997-2000/remont/testing-diagnostics/#engine-controls-tests-wcodes). If no continuity is present, problem is intermittent. If continuity is present, replace HO2S.

DTC P0138 HO2S RESISTANCE CHECK

DTC P0139 & P0159: HO2S AFTER TWC

Erase DTCs. Road test vehicle. If additional DTCs are set, perform diagnosis on these DTCs first. Erase DTCs. If DTCs P0139 and/or P0159 reoccur, replace HO2S.

DTC P0140: HO2S AFTER TWC OPEN CIRCUIT (CYLS. 1-3)

1. Disconnect all 4 HO2S connectors. (Scheme 5)and (Scheme 6). Turn ignition on. Connect voltmeter between HO2S No. 1 connector after TWC terminals No. 3 (Brown wire) and No. 4 (White wire). About 450 millivolts should be present. Connect voltmeter between terminal No. 3 (Brown wire) and ground. About 720 millivolts should be present. If voltages are to specification, go to next step. If voltages are not to specification, check wiring for an open circuit. If wiring is okay, replace ECM.
2. Reconnect HO2S connectors. Run engine at high engine speed to heat HO2S. Sharply depress accelerator several times. Using scan tool, read HO2S voltage. If HO2S voltage fluctuates between 100-800 millivolts, go to next step. If HO2S voltage does not fluctuate between 100-800 millivolts, replace HO2S.
3. Disconnect HO2S connector No. 1 behind TWC. Connect ohmmeter between HO2S connector terminals No. 1 (Red/White wire) and No. 2 (Brown wire). About 1.8-2.5 ohms should be present. Connect ohmmeter between HO2S connector terminal No. 1 (Red/White wire) and HO2S housing, then between HO2S connector terminal No. 2 (Brown wire) and HO2S housing. No continuity should be present. If resistances are not to specification, repair wiring as necessary.

DTC P0150: HO2S AHEAD OF TWC SHORT CIRCUIT (CYLS. 4-6)

1. Run engine to heat HO2S. Connect scan tool and read voltage of HO2S No. 2 ahead of TWC. If voltage fluctuates between 100-800 millivolts, go to next step. If voltage does not fluctuate between 100-800 millivolts, disconnect HO2S connector. Connect voltmeter between connector terminals No. 3 (Brown wire) and No. 4 (White wire). (Scheme 5)and (Scheme 6). If 450 millivolts are present, replace HO2S. If no voltage is present, go to next step.
2. Disconnect HO2S and ECM connectors. Connect ohmmeter between ECM connector terminal No. 18 (White wire) and HO2S connector terminal No. 4. If continuity is present, go to next step. If continuity is not present, replace wiring harness.
3. Disconnect all HO2S connectors. Measure resistance between ECM connector terminal No. 46 (Brown wire) and HO2S connector terminal No. 3. If continuity is present, go to next step. If continuity is not present, repair wiring harness.
4. Reconnect ECM connector. Disconnect only HO2S No. 2 connector ahead of TWC. Connect voltmeter between connector terminals No. 3 (Brown wire) and No. 4 (White wire). Turn ignition on. If reading is 400-500 millivolts, problem is intermittent. If reading is not 400-500 millivolts, replace ECM.

DTC P0151: HO2S AHEAD OF TWC SHORT TO GROUND (CYLS. 4-6)

1. Disconnect all 4 HO2S connectors. (Scheme 5)and (Scheme 6). Turn ignition on. Connect voltmeter between HO2S No. 2 connector ahead of TWC terminals No. 3 (Brown wire) and No. 4 (White wire). About 450 millivolts should be present. Connect voltmeter between HO2S connector terminal No. 3 (Brown wire) and ground. About 720 millivolts should be present. If voltages are to specification, go to next step. If voltages are not to specification, check wiring for a short circuit to ground. If wiring is okay, replace ECM.
2. Disconnect only HO2S No. 2 connector ahead of TWC. Connect ohmmeter between HO2S terminals. See «DTC P0151 HO2S RESISTANCE CHECK»(/porsche/911-carrera-4/996-1997-2000/remont/testing-diagnostics/#engine-controls-tests-wcodes). If no continuity is present, problem is intermittent. If continuity is present, replace HO2S.

DTC P0151 HO2S RESISTANCE CHECK

DTC P0152: HO2S AHEAD OF TWC SHORT TO VOLTAGE (CYLS. 4-6)

1. Disconnect all 4 HO2S connectors. (Scheme 5)and (Scheme 6). Turn ignition on. Connect voltmeter between HO2S No. 2 connector behind TWC terminals No. 3 (Brown wire) and No. 4 (White wire). About 450 millivolts should be present. Connect voltmeter between terminal No. 3 and ground. About 720 millivolts should be present. If voltages are to specification, go to next step. If voltages are not to specification, check wiring for a short circuit to voltage. If wiring is okay, replace ECM.
2. Disconnect only HO2S No. 2 connector behind TWC. Connect ohmmeter between HO2S terminals. See «DTC P0152 HO2S RESISTANCE CHECK»(/porsche/911-carrera-4/996-1997-2000/remont/testing-diagnostics/#engine-controls-tests-wcodes). If no continuity is present, problem is intermittent. If continuity is present, replace HO2S.

DTC P0152 HO2S RESISTANCE CHECK

DTC P0153: HO2S AHEAD OF TWC

See DTC P0133 & P0153: HO2S AHEAD OF TWC test.

DTC P0154: HO2S AHEAD OF TWC OPEN CIRCUIT (CYLS. 4-6)

1. Disconnect all 4 HO2S connectors. (Scheme 5)and (Scheme 6). Turn ignition on. Connect voltmeter between HO2S No. 2 connector ahead of TWC terminals No. 3 (Brown wire) and No. 4 (White wire). About 450 millivolts should be present. Connect voltmeter between terminal No. 3 (Brown wire) and ground. About 720 millivolts should be present. If voltages are to specification, go to next step. If voltages are not to specification, check wiring for an open circuit. If wiring is okay, replace ECM.
2. Reconnect HO2S connectors. Run engine at high engine speed to heat HO2S. Using scan tool, read HO2S voltage. If voltage fluctuates between 100-800 millivolts, HO2S is okay. If HO2S voltage does not fluctuate between 100-800 millivolts, go to next step.
3. Disconnect HO2S connector No. 2 ahead of TWC. Connect ohmmeter between HO2S connector terminals No. 1 (Red/White wire) and No. 2 (Brown wire). About 1.8-2.5 ohms should be present. Connect ohmmeter between HO2S connector terminal No. 1 and HO2S housing, then between HO2S connector terminal No. 2 and HO2S housing. No continuity should be present. If resistances are to specification, wiring is okay. If resistances are not to specification, repair wiring as necessary.

DTC P0156: HO2S AFTER TWC SHORT IN WIRING (CYLS. 4-6)

1. Disconnect all 4 HO2S connectors. (Scheme 5)and (Scheme 6). Turn ignition on. Connect voltmeter between HO2S No. 2 connector after TWC terminals No. 3 (Brown wire) and No. 4 (White wire). About 450 millivolts should be present. Connect voltmeter between terminal No. 3 (Brown wire) and ground. About 720 millivolts should be present. If voltages are to specification, go to next step. If voltages are not to specification, check wiring for a short circuit to ground. If wiring is okay, replace ECM.
2. Reconnect HO2S connectors. Run engine at high engine speed to heat HO2S. Depress accelerator pedal quickly several times. Using scan tool, read HO2S voltage. If voltage fluctuates between 100-800 millivolts, HO2S is okay. If HO2S voltage does not fluctuate between 100-800 millivolts, replace HO2S.

DTC P0157: HO2S AFTER TWC SHORT TO GROUND (CYLS. 4-6)

1. Disconnect all 4 HO2S connectors. (Scheme 5)and (Scheme 6). Turn ignition on. Connect voltmeter between HO2S No. 2 connector behind TWC terminals No. 3 (Brown wire) and No. 4 (White wire). About 450 millivolts should be present. Connect voltmeter between terminal No. 3 (Brown wire) and ground. About 720 millivolts should be present. If voltages are to specification, go to next step. If voltages are not to specification, check wiring for a short circuit to ground. If wiring is okay, replace ECM.
2. Disconnect only HO2S No. 2 connector behind TWC. Connect ohmmeter between HO2S terminals. See «DTC P0157 HO2S RESISTANCE CHECK»(/porsche/911-carrera-4/996-1997-2000/remont/testing-diagnostics/#engine-controls-tests-wcodes). If no continuity is present, problem is intermittent. If continuity is present, replace HO2S.

DTC P0157 HO2S RESISTANCE CHECK

DTC P0158: HO2S AFTER TWC SHORT TO VOLTAGE (CYLS. 4-6)

1. Disconnect all 4 HO2S connectors. (Scheme 5)and (Scheme 6). Turn ignition on. Connect voltmeter between HO2S No. 2 connector behind TWC terminals No. 3 (Brown wire) and No. 4 (White wire). About 450 millivolts should be present. Connect voltmeter between terminal No. 3 (Brown wire) and ground. About 720 millivolts should be present. If voltages are to specification, go to next step. If voltages are not to specification, check wiring for a short circuit to voltage. If wiring is okay, replace ECM.
2. Disconnect only HO2S No. 2 connector behind TWC. Connect ohmmeter between HO2S terminals. See «DTC P0158 HO2S RESISTANCE CHECK»(/porsche/911-carrera-4/996-1997-2000/remont/testing-diagnostics/#engine-controls-tests-wcodes). If no continuity is present, problem is intermittent. If continuity is present, replace HO2S.

DTC P0158 HO2S RESISTANCE CHECK

DTC P0159: HO2S AFTER TWC

See DTC P0139 & P0159: HO2S AFTER TWC test.

DTC P0160: HO2S AFTER TWC OPEN CIRCUIT (CYLS. 4-6)

1. Disconnect all 4 HO2S connectors. (Scheme 5)and (Scheme 6). Turn ignition on. Connect voltmeter between HO2S No. 2 connector after TWC terminals No. 3 (Brown wire) and No. 4 (White wire). About 450 millivolts should be present. Connect voltmeter between terminal No. 3 (Brown wire) and ground. About 720 millivolts should be present. Start engine and run at high speed for 3 minutes. Connect voltmeter between connector terminals No. 1 (Red/White wire) and No. 2 (Brown/Yellow wire). Battery voltage should be present. If voltages are to specification, go to next step. If voltages are not to specification, check wiring for an open circuit. If wiring is okay, replace ECM.
2. Reconnect HO2S connectors. Run engine at high engine speed to heat HO2S. Using scan tool, read HO2S voltage. If voltage fluctuates between 100-800 millivolts, HO2S is okay. If HO2S voltage does not fluctuate between 100-800 millivolts, go to next step.
3. Disconnect HO2S connector No. 2 after TWC. Connect ohmmeter between HO2S connector terminals No. 1 (Red/White wire) and No. 2 (Brown/Yellow wire). About 1.8-2.5 ohms should be present. Connect ohmmeter between HO2S connector terminal No. 1 (Red/White wire) and HO2S housing, then between HO2S connector terminal No. 2 (Brown/Yellow wire) and HO2S housing. No continuity should be present. If resistances are to specification, wiring is okay. If resistances are not to specification, repair wiring as necessary.

DTC P0300-P0306: MISFIRE

1. Remove heater duct at left rear engine compartment. Remove valve cover at fuel distributor test connection. Connect pressure gauge to test connection. Remove ECM relay from fuse/relay panel. (Scheme 7) Connect fused jumper wire between fuse/relay panel terminals No. 30 and 87b. (Scheme 8) Activate fuel pump with scan tool. With engine off, fuel pressure should be 55.1 psi (3.8 kg/cm 2 ). With engine at idle, fuel pressure should be 47.8 psi (3.3 kg/cm 2 ). If fuel pressure is okay, go to next step. If fuel pressure is not okay, fuel pump is defective.
2. Remove heater fan at left rear of engine compartment. Remove fuel return line at fuel pressure regulator. Connect Hose (9507) to pressure regulator and place other end in a measuring unit. Activate fuel pump as outlined in previous step. After 30 seconds, measuring unit should contain at least.8 qt. (.8 L). If fuel volume is not okay, fuel pump is defective. If fuel volume is okay, use scan tool and check injector operation. Repair as necessary. If injector operation is okay, check air intake system for leaks. Repair as necessary.

Scheme 7

Scheme 8

DTC P0326, P0331 & P1386: KNOCK SENSOR SIGNAL INCORRECT

1. If DTC P1386 is present, replace ECM. If DTC P0326 or P0331 is present, ensure knock sensor on sensor bridge is correctly tightened to 15 ft. lbs. (20 N.m). If knock sensor is tightened correctly, check knock sensor bridge for cracks. Replace knock sensor bridge as necessary. If knock sensor bridge is okay, ensure knock sensor bridge is correctly tightened to 8 ft. lbs. (10 N.m). Tighten knock sensor bridge as necessary. If all components are okay, go to next step.
2. Disconnect knock sensor connectors. (Scheme 9)and (Scheme 10). Disconnect ECM connector. Ensure continuity is present between ECM connector terminals No. 70 (White wire), No. 40 (White wire), No. 71 (White wire) and appropriate knock sensor connector. Repair wiring as necessary. If continuity is present, go to next step.
3. Check continuity between knock sensor connector No. 1, terminal No. 3 (no wire color available) and ground, and between knock sensor connector No. 2, terminal No. 3 (no wire color available) and ground. Repair wiring as necessary. If wiring is okay, go to next step.
4. Connect ohmmeter between ECM connector terminal No. 70 (White wire) and ground, then between ECM connector terminal No. 40 (White wire) and ground. If no continuity is present, go to next step. If continuity is present, repair wiring for a short circuit to ground.
5. Turn ignition on. Connect voltmeter between ECM connector terminal No. 70 (White wire), No. 40 (White wire) and No. 71 (White wire) and ground. If voltage is present, repair wiring for a short circuit to voltage. If no voltage is present, replace knock sensors.

Scheme 9

Scheme 10

DTC P0336: CRANKSHAFT POSITION SENSOR SIGNAL INCORRECT

1. Disconnect Crankshaft Position (CKP) sensor connector. Connect ohmmeter between CKP sensor connector terminals No. 1 (White wire) and No. 2 (Brown wire). If 480-600 ohms are present, go to next step. If 480-600 ohms are not present, replace CKP sensor.
2. Connect ohmmeter between CKP connector terminals No. 1 (White wire) and No. 3. If no continuity is present, go to next step. If continuity is present, replace CKP sensor.
3. Use an oscilloscope and check CKP sensor signal. See ENGINE SENSORS & SWITCHES in «SYSTEM/COMPONENT TESTS»(/porsche/911-carrera-4/996-1997-2000/remont/testing-diagnostics/#engine-controls-systemcomponent-tests) article. If signal is okay, check wiring between CKP sensor and ECM for an open or short circuit. If signal is not okay, check CKP sensor gap. Gap should be .031-.047" (.8-1.2 mm). Adjust with spacer disks as necessary.

DTC P0341: CAMSHAFT POSITION (CMP) SENSOR SIGNAL INCORRECT

1. Disconnect ignition distributor connector. Turn ignition on. Connect voltmeter between CMP sensor connector terminals No. 1 (Brown wire) and No. 3 (White wire). If about 5 volts are present, go to next step. If about 5 volts are not present, repair wiring.
2. Turn ignition off. Disconnect ECM connector. Connect ohmmeter between ECM connector terminal No. 53 (White wire) and ignition distributor connector terminal No. 3, then connect ohmmeter between ignition distributor connector terminal No. 1 (Brown wire) and ground. If continuity is present, go to next step. If continuity is not present, repair open circuit in wiring.
3. Backprobe voltmeter at in-line connector between ECM and CMP sensor between terminals No. 1 (White wire) and No. 15 (Brown wire). If about 4 volts are present, go to next step. If about 4 volts are not present, replace ignition distributor.
4. Turn ignition off. Disconnect ignition distributor and ECM connectors. Connect ohmmeter between ECM connector terminal No. 21 (Black/White wire) and ignition distributor connector terminal No. 2. If continuity is present, replace ECM. If continuity is not present, repair open circuit in wiring.

DTC P0410 & DTC P1411: SECONDARY AIR INJECTION SYSTEM

1. Using scan tool, select secondary air injection (AIR) pump in SHORT TEST. If air pump operates, go to next step. If air pump does not operate, check fuse No. 48 on relay panel on left side of engine compartment. Repair as necessary. If fuse is okay, check relay and wiring. If relay and wiring are okay, replace air pump.
2. Disconnect 2-pin air switching valve connector on AIR pump. Connect voltmeter between air switching valve connector terminals. Using scan tool, activate air pump. If battery voltage is not present, check wiring. Repair wiring as necessary. If battery voltage is present, activate air pump with scan tool. Remove vacuum hose from air switching valve. If vacuum is present, check air supply from AIR pump, to air switching valve, and to air supply line to cylinder heads. Repair as necessary.

DTC P0420 & P0430: TWC CONVERSION TOO LOW

Check if other DTCs are present. If other DTCs are present, repair those DTCs first. Erase DTCs and road test vehicle. If DTCs reoccur, replace TWC.

DTC P0441: FUEL TANK VENTILATION SYSTEM MALFUNCTION

1. Check flow through EVAP canister purge valve. Flow direction can be checked by determining position of electric connector. Ensure connector points toward intake manifold. Repair as necessary. If connector location is okay, go to next step.
2. Connect scan tool. In menu DRIVE LINKS, select TANK VENT. If EVAP canister purge valve switches, go to next step. If EVAP canister purge valve does not switch, check voltage supply to valve. Repair as necessary.
3. Check EVAP canister purge valve and hose between EVAP canister purge valve and intake system for leaks. Repair as necessary. If no vacuum leaks are present, check hoses and hose distributor for restrictions. Check EVAP canister. Repair as necessary.

DTC P0444: FUEL GRAVITY VALVE EVAP CANISTER PURGE VALVE OPEN CIRCUIT

1. Disconnect EVAP canister purge valve connector. Connect voltmeter between EVAP canister purge valve connector terminal No. 1 (Red/White wire) and ground. Turn ignition on. If battery voltage is present, go to next step. If battery voltage is not present, repair open circuit in Red/White wire.
2. Turn ignition off. Connect ohmmeter between EVAP canister purge valve connector terminals No. 1 (Red/White wire) and No. 2 (Yellow/Green wire). If resistance is about 26 ohms at 68°F (20°C), go to next step. If resistance is not about 26 ohms at 68°F (20°C), replace EVAP canister purge valve.
3. Disconnect ECM connector. Connect ohmmeter between EVAP canister purge valve connector terminal No. 2 (Yellow/Green wire) and ECM connector terminal No. 61. If continuity is present, replace ECM. If continuity is not present, repair open circuit in Yellow/Green wire.

DTC P0445: FUEL GRAVITY VALVE EVAP CANISTER PURGE VALVE SHORT CIRCUIT

1. Connect scan tool and determine fault type. If fault type is above upper limit, short to voltage, or rich, go to next step. If fault type is below lower limit, short to ground, or lean, disconnect EVAP canister purge valve connector. Disconnect ECM connector. Connect ohmmeter between EVAP canister purge valve connector terminal No. 2 (Yellow/Green wire) and ground. If continuity is present, repair Yellow/Green wire for a short circuit to ground. If continuity is not present, replace ECM.
2. Disconnect EVAP canister purge valve and ECM connectors. Connect voltmeter between EVAP canister purge valve connector terminal No. 2 (Yellow/Green wire) and ground. Turn ignition on. If battery voltage is present, check Yellow/Green wire for a short circuit to voltage. If no voltage is present, replace ECM.

DTC P0501: VEHICLE SPEED SENSOR (VSS) NOT IN SPECIFIED RANGE

1. Using scan tool, check ABS control module memory. If fault for right rear speed sensor is stored in memory, go to next step. If fault for right rear speed sensor is not stored in memory, go to step 3).
2. Check resistance at right rear wheel speed sensor. If 1.6-1.8 k/ohms are present, check for short to voltage or ground in wiring between ABS control module to right rear wheel speed sensor. See ANTI-LOCK BRAKE SYSTEM article in BRAKES section. Repair as necessary. If 1.6-1.8 k/ohms are not present, replace right wheel speed sensor.
3. Check White/Red wire between ABS control module terminals No. 35 and 36, and ECM connector terminal No. 79 for no continuity or short to voltage or ground. ABS control module is located on right front side of luggage compartment. Repair as necessary. If wiring is okay, check speed signal with oscilloscope. (Scheme 11) Oscilloscope pattern should toggle between 0-12 volts. If speed signal is okay, replace ECM. If speed signal is not okay, replace ABS control module.

Scheme 11

DTC P0506 & P0507: IDLE AIR CONTROL (IAC)

1. To diagnose DTC P0507, go to next step. To diagnose DTC P0506, check air cleaner for damage or obstructions. Replace as necessary. If air cleaner is okay, ensure bypass hose is correctly routed and is not restricted. Repair as necessary. If bypass hose is okay, use scan tool and activate IAC valve. A clicking sound should be heard. Replace IAC valve as necessary.
2. Use scan tool and activate IAC valve. A clicking sound should be heard. Replace IAC valve as necessary. If IAC valve operates correctly, check intake air system for leaks. Repair as necessary.

DTC P0604, P0605 & P1640: ECM FAULTY

These DTCs set if a fault is present in ECM. Replace ECM.

DTC P1102 & P1107: HO2S HEATING ABOVE UPPER LIMIT

1. Disconnect HO2S connector(s). (Scheme 5)and (Scheme 6). Connect ohmmeter between HO2S terminals No. 1 (Red/White wire) and No. 2 (Brown/Yellow wire). If resistance is 1.8-2.5 ohms, go to next step. If resistance is not 1.8-2.5 ohms, replace HO2S.
2. Start and run engine at high speed for 3 minutes. Connect voltmeter between HO2S terminals No. 1 (Red/White wire) and No. 2 (Brown/Yellow wire). Battery voltage should be present. Connect voltmeter between HO2S terminal No. 2 (Brown/Yellow wire) and ground. No voltage should be present. Turn engine off. Disconnect ECM connector. Remove ECM relay. (Scheme 7) Connect jumper wire between relay base terminals No. 30 and 87b. Connect voltmeter between HO2S connector terminal No. 2 (Brown/Yellow wire) and ground. No voltage should be present. If voltages are to specification, replace ECM. If voltages are not to specification, repair wiring for a short circuit to voltage.

DTC P1105 & P1110: HO2S HEATING ABOVE UPPER LIMIT

1. Disconnect HO2S connector(s). (Scheme 5)and (Scheme 6). Connect ohmmeter between HO2S connector terminals No. 1 (Black wire) and No. 2 (Red/Black wire). If resistance is 1.8-2.5 ohms, go to next step. If resistance is not 1.8-2.5 ohms, replace HO2S.
2. Start and run engine at high speed for 10 minutes. Connect voltmeter between HO2S connector terminals No. 1 (Black wire) and No. 2 (Red/Black wire). Battery voltage should be present. Connect voltmeter between HO2S connector terminal No. 2 (Red/Black wire) and ground. No voltage should be present. Turn engine off. Disconnect ECM connector. Remove ignition, injection, and HO2S heating relay. Connect jumper wire between relay base terminals No. 30 and 87. Connect voltmeter between HO2S connector terminal No. 2 (Red/Black wire) and ground. No voltage should be present. If voltages are to specification, replace ECM. If voltages are not to specification, repair wiring for a short circuit to voltage.

DTC P1115 & P1119: HO2S HEATING BELOW LOWER THRESHOLD

1. Disconnect HO2S connector(s). (Scheme 5)and (Scheme 6). Connect ohmmeter between HO2S connector terminals No. 1 (Red/White wire) and No. 2 (Brown wire). Resistance should be 1.8-2.5 ohms. Connect ohmmeter between HO2S terminal No. 1 and HO2S housing. No continuity should be present. If resistances are to specification, go to next step. If resistances are not to specification, replace HO2S.
2. Disconnect ECM connector. Connect ohmmeter between ECM connector terminal No. 30 (Brown wire) and HO2S connector terminal No. 2 (Brown wire). Continuity should be present. Connect ohmmeter between HO2S connector terminal No. 2 (Brown wire) and ground. No continuity should be present. Remove ECM relay. (Scheme 7) Connect jumper wire between relay base terminals No. 30 and 87b. Connect voltmeter between HO2S connector terminal No. 2 (Brown wire) and ground. No voltage should be present. If resistances and voltage are to specification, go to next step. If resistances and voltage are not to specification, repair wiring as necessary.
3. Start and run engine at high speed for 3 minutes. Connect voltmeter between HO2S connector terminals No. 1 (Red/White wire) and No. 2 (Brown wire). If battery voltage is present, system is okay. If battery voltage is not present, replace ECM.

DTC P1117 & P1121: HO2S HEATING BELOW LOWER THRESHOLD

1. Disconnect HO2S connector(s). (Scheme 5)and (Scheme 6). Connect ohmmeter between HO2S connector terminals No. 1 (Red/White wire) and No. 2 (Brown/Yellow wire). Resistance should be 1.8-2.5 ohms. Connect ohmmeter between HO2S connector terminal No. 1 (Red/White wire) and ground. If no continuity is present, go to next step. If continuity is present, replace HO2S.
2. Disconnect ECM connector. Connect ohmmeter between ECM connector terminal No. 1 (Brown/Yellow wire) and HO2S connector terminal No. 2. Continuity should be present. Connect ohmmeter between HO2S connector terminal No. 2 (Brown/Yellow wire) and ground. No continuity should be present. Remove ECM relay. (Scheme 7) Connect jumper wire between relay base terminals No. 30 and 87b. Connect voltmeter between HO2S connector terminal No. 2 (Brown/Yellow wire) and ground. No voltage should be present. If resistances and voltage are to specification, go to next step. If resistances and voltage are not to specification, repair wiring as necessary.
3. Start and run engine at high speed for 3 minutes. Connect voltmeter between HO2S connector terminals No. 1 (Red/White wire) and No. 2 (Brown/Yellow wire). If battery voltage is present, system is okay. If battery voltage is not present, replace ECM.

DTC P1123, P1125, P1127 & P1129: FUEL MIXTURE

Check fuel pressure. See DTC P0300-P0306: MISFIRE . Repair as necessary. If fuel pressure is okay, check fuel pressure regulator, vacuum connection, and fuel return line. Repair as necessary. If all components are okay, check fuel injector for leaks.

DTC P1124, P1126, P1128 & P1130: FUEL MIXTURE

1. Check DTC memory. If other DTCs are present, repair those DTCs first. If no other DTCs are present, go to next step.
2. Check exhaust and air intake system for leaks. Repair as necessary. If exhaust and air intake system are okay, check fuel pressure and volume supply of fuel pump. See «DTC P0300-P0306: MISFIRE»(/porsche/911-carrera-4/996-1997-2000/remont/testing-diagnostics/#engine-controls-tests-wcodes__dtc-p0300-p0306-misfire) . If fuel pressure and volume supply of fuel pump are okay, check fuel injectors for carbon contamination. Repair as necessary.

DTC P1140: LOAD SIGNAL

Check cruise control cable and adjust as necessary. See CRUISE CONTROL SYSTEM article in ACCESSORIES/SAFETY EQUIPMENT section. If cruise control cable adjustment is okay, check Throttle Position Sensor (TPS) values at closed and open throttle position. See DTC P0122 & P0123: THROTTLE POSITION (TP) SENSOR . Repair as necessary. If TPS is okay, check intake air system for leaks. Repair as necessary.

DTC P1213-P1218, P1225-P1230 & P1237-P1242: FUEL INJECTOR

Disconnect injector connector. Connect ohmmeter between injector terminals No. 1 and 2. If resistance is 15-17 ohms, check wiring between fuel injector and ECM for a short circuit to ground or voltage, or an open circuit. Repair as necessary. If wiring is okay, replace ECM. If resistance is not 15-17 ohms, replace injector.

DTC P1386: KNOCK SENSOR SIGNAL INCORRECT

See DTC P0326, P0331 & P1386: KNOCK SENSOR SIGNAL INCORRECT test.

DTC P1411: SECONDARY AIR INJECTION SYSTEM

See DTC P0410 & DTC P1411: SECONDARY AIR INJECTION SYSTEM test.

DTC P1455, P1456 & P1457: A/C COMPRESSOR CONTROL

1. If DTC P1455 is set, remove A/C relay. Connect ohmmeter between ECM connector terminal 62 (Green/White wire) and A/C relay connector terminal No. 2 (Green/White wire). If continuity is present, system is okay. If continuity is not present, repair open circuit in White/Green wire.
2. If DTC P1456 is set, remove A/C relay. Disconnect ECM connector. Connect voltmeter between A/C relay connector terminal No. 2 (Green/White wire) and ground. If no voltage is present, system is okay. If battery voltage is present, repair short circuit to voltage in Green/White wire.
3. If DTC P1457 is set, remove A/C relay. Disconnect ECM connector. Connect ohmmeter between A/C relay connector terminal No. 2 (Green/White wire) and ground. If no continuity is present, system is okay. If continuity is present, repair short circuit to ground in Green/White wire.

DTC P1458: A/C COMPRESSOR CONTROL

1. Disconnect A/C-heater control unit and ECM connector. Connect ohmmeter between ECM connector terminal No. 11 (Blue wire) and A/C-heater control unit connector terminal K23 (Green/Blue wire). If continuity is present, go to next step. If continuity is not present, check Blue and Green/Blue wires, and in-line connectors for an open circuit.
2. Disconnect A/C pressure switch connector. Connect ohmmeter between ECM connector terminal No. 38 (White/Orange wire) and ground. If no continuity is present, go to next step. If continuity is present, check White/Orange wire for a short circuit to ground.
3. Connect ohmmeter between A/C-heater control unit connector terminal K24 (Black wire) and ground. If no continuity is present, go to next step. If continuity is present, check Black wire for a short circuit to ground.
4. Reconnect A/C-heater control unit connector. Ensure climate control switch is off. Connect ohmmeter (backprobe) between A/C-heater control unit connector terminal K24 (Black wire) and ground. If no continuity is present, replace ECM. If continuity is present, replace A/C-heater control unit. See A/C-HEATER SYSTEM - AUTOMATIC article in AIR CONDITIONING & HEAT section.

DTC P1501, P1502 & P1541: FUEL PUMP RELAY END STAGE

1. Record DTC. If DTC P1501 is set, go to next step. If DTC P1502 is set, go to step 3). If DTC P1541 is set, go to step 4).
2. Remove ECM relay. (Scheme 7) Connect ohmmeter between ECM relay terminals No. 85 (-) and 86 (+). If about 1200 k/ohms are not present, replace ECM relay. If about 1200 k/ohms are present, disconnect connector X4/1 located under driver's seat. (Scheme 12) Connect ohmmeter between ECM relay connector terminal No. 6 (Yellow/Green wire) and ground. If continuity is present, repair short circuit to ground in Yellow/Green wire. If continuity is not present, disconnect ECM connector. Connect ohmmeter between connector X4/1 terminal No. 4 (Yellow/Green wire) and ground. If continuity is not present, replace ECM. If continuity is present, repair short circuit to ground in Yellow/Green wire.
3. If DTC 1502 is set, remove ECM relay. Connect ohmmeter between ECM relay terminals No. 85 (-) and 86 (+). If about 1200 k/ohms are not present, replace ECM relay. If about 1200 k/ohms are present, disconnect connector X4/1 located under driver's seat. (Scheme 12) Turn ignition on. Connect voltmeter between ECM relay connector terminal No. 6 (Yellow/Green wire) and ground. If battery voltage is present, check wiring for a short circuit to voltage. If no voltage is present, disconnect ECM connector. Connect voltmeter between connector X4/1 terminal No. 4 (Yellow/Green wire) and ground. Connector X4/1 is located under driver's seat. If battery voltage is present, check Yellow/Green wire for a short circuit to voltage. If no voltage is present, replace ECM.
4. If DTC 1541 is set, remove ECM relay. Disconnect ECM connector. Connect ohmmeter between ECM relay base terminal No. 6 (Yellow/Green wire) and ECM connector terminal No. 27. If continuity is present, replace ECM. If continuity is not present, check for poor terminal contact at connector X4/1 terminal No. 4. Connector X4/1 is located under driver's seat. (Scheme 12) Repair as necessary.

Scheme 12

DTC P1510, P1513 & P1514: IAC VALVE

1. Record DTC. If DTC P1510 is set, go to next step. If DTC P1513 is set, go to step 3). If DTC P1514 is set, go to step 4).
2. If DTC P1510 is set, disconnect IAC valve connector. Connect ohmmeter between IAC valve connector terminals No. 2 (Red/White wire) and No. 3 (Blue wire). If about 10-12 ohms are not present at 68°F (20°C), replace IAC valve. If about 10-12 ohms are present at 68°F (20°C), disconnect ECM connector. Connect voltmeter between ECM connector terminal No. 29 (Blue wire) and ground. If zero volts are present, replace ECM. If battery voltage is present, check Blue wire for short circuit to voltage.
3. If DTC P1513 is set, disconnect IAC valve connector. Connect ohmmeter between IAC valve connector terminals No. 2 (Red/White wire) and No. 3 (Blue wire). If about 10-12 ohms are not present at 68°F (20°C), replace IAC valve. If about 10-12 ohms are present at 68°F (20°C), disconnect ECM connector. Connect ohmmeter between ECM connector terminal No. 29 (Blue wire) and ground. If no continuity is present, replace ECM. If continuity is present, check Blue wire for short circuit to ground.
4. If DTC P1514 is set, disconnect IAC valve connector. Connect ohmmeter between IAC valve connector terminals No. 2 (Red/White wire) and No. 3 (Blue wire). If about 10-12 ohms are not present at 68°F (20°C), replace IAC valve. If about 10-12 ohms are present at 68°F (20°C), disconnect ECM connector. Connect voltmeter between ECM connector terminal No. 2 (Black/White wire) and ground. If no voltage is present, replace ECM. If battery voltage is present, check Black/White wire for a short circuit to ground.

DTC P1512, P1515 & P1516: INTAKE MANIFOLD RESONANCE FLAP

1. Record DTC. If DTC P1512 is set, go to next step. If DTC P1515 is set, go to step 3). If DTC P1516 is set, go to step 4).
2. Disconnect change-over valve connector. Connect ohmmeter between change over valve terminals No. 1 (Gray/White wire) and No. 2 (Red/White wire). If resistance is not 25-35 ohms, replace change-over valve. If resistance is 25-35 ohms, disconnect ECM and change-over valve connectors. Connect voltmeter between ECM connector terminal No. 59 (Gray/White wire) and ground. Turn ignition on. If no voltage is present, system is okay. If battery voltage is present, repair short circuit to voltage in Gray/White wire.
3. If DTC 1515 is present, disconnect change-over valve connector. Connect ohmmeter between change over valve terminals No. 1 (Gray/White wire) and No. 2 (Red/White wire). If resistance is not 25-35 ohms, replace change-over valve. If resistance is 25-35 ohms, disconnect ECM and change-over valve connectors. Connect ohmmeter between ECM connector terminal No. 59 (Gray/White wire) and ground. If no continuity is present, system is okay. If continuity is present, repair short circuit to ground in Gray/White wire.
4. If DTC 1516 is present, disconnect change-over valve connector. Connect ohmmeter between change over valve terminals No. 1 (Gray/White wire) and No. 2 (Red/White wire). If resistance is not 25-35 ohms, replace change-over valve. If resistance is 25-35 ohms, disconnect ECM and change-over valve connectors. Connect ohmmeter between ECM connector terminal No. 59 (Gray/White wire) and change-over valve connector terminal No. 1. If continuity is present, system is okay. If continuity is not present, check Gray/White wire for an open circuit.

DTC P1541: FUEL PUMP RELAY END STAGE

See DTC P1501, P1502 & P1541: FUEL PUMP RELAY END STAGE test.

DTC P1551, P1552 & P1553: IAC VALVE/ECM

1. Record DTC. If DTC P1551 is set, go to next step. If DTC P1552 is set, go to step 3). If DTC P1553 is set, go to step 4).
2. Disconnect IAC valve connector. Connect ohmmeter between IAC valve connector terminals No. 1 (Black/White wire) and No. 2 (Red/White wire). If about 10-12 ohms are not present at 68°F (20°C), replace IAC valve. If about 10-12 ohms are present at 68°F (20°C), connect ohmmeter between ECM connector terminal No. 2 (Black/White wire) and IAC valve connector terminal No. 1. If continuity is present, replace ECM. If continuity is not present, check Black/White wire for an open circuit.
3. If DTC P1552 is set, disconnect IAC valve connector. Connect ohmmeter between IAC valve connector terminals No. 1 (Black/White wire) and No. 2 (Red/White wire). If about 10-12 ohms are not present at 68°F (20°C), replace IAC valve. If about 10-12 ohms are present at 68°F (20°C), connect ohmmeter between ECM connector terminal No. 2 (Black/White wire) and ground. If no continuity is present, replace ECM. If continuity is present, check Black/White wire for short circuit to ground.
4. If DTC P1553 is set, disconnect IAC valve connector. Connect ohmmeter between IAC valve connector terminals No. 1 (Black/White wire) and No. 2 (Red/White wire). If about 10-12 ohms are not present at 68°F (20°C), replace IAC valve. If about 10-12 ohms are present at 68°F (20°C), connect voltmeter between ECM connector terminal No. 2 (Black/White wire) and ground. If no voltage is present, replace ECM. If battery voltage is present, check Black/White wire for a short circuit to voltage.

DTC P1570 & P1571: IMMOBILIZER

1. Disconnect immobilizer control module and ECM connectors. Immobilizer control module is located next to ECM, under driver's seat. Connect ohmmeter between ECM connector terminal No. 55 (Brown wire) and immobilizer control module connector terminal No. 9. If continuity is present, go to next step. If continuity is not present, repair open circuit in Brown wire.
2. Locate connector X4/2 located under driver's seat. (Scheme 12) Connect ohmmeter between ECM side of connector X4/2, terminal No. 12 (Orange/Black wire) and ECM connector terminal No. 88 (Orange/White wire). If continuity is present, go to next step. If continuity is not present, repair open circuit in Orange/Black or Orange/White wire.
3. Connect ohmmeter between immobilizer control module side of connector X4/2, terminal No. 12 (Orange/Black wire) and immobilizer control module connector terminal No. 9. If continuity is present, go to next step. If continuity is not present, repair open circuit in Orange/Black wire.
4. Connect ohmmeter between ECM connector terminal No. 88 (Orange/White wire) and ground. If no continuity is present, go to next step. If continuity is present, check wiring for a short circuit to ground.
5. Connect voltmeter between ECM connector terminal No. 88 (Orange/White wire) and ground. If battery voltage is present, check wiring for a short circuit to voltage. If no voltage is present, replace immobilizer control module. See ANTI-THEFT, DRIVE BLOCK & DOOR LOCK SYSTEMS in ACCESSORIES/SAFETY EQUIPMENT section.

DTC P1593, P1594 & P1595: INTAKE MANIFOLD LENGTH TUNING

1. Record DTC. If DTC P1593 is set, go to next step. If DTC P1594 is set, go to step 4). If DTC P1595 is set, go to step 5).
2. If DTC 1593 is set, disconnect change-over valve connector. Connect ohmmeter between change-over valve terminals No. 1 (Green/White wire) and No. 2 (Red/White wire). If about 25-35 ohms are present, go to next step. If about 25-35 ohms are not present, replace change-over valve.
3. Disconnect ECM connector. Connect ohmmeter between ECM connector terminal No. 35 (Green/White wire) and change-over valve connector terminal No. 1. If continuity is present, system is okay. If continuity is not present, repair open circuit in Green/White wire circuit.
4. If DTC 1594 is set, disconnect ECM and change-over valve connectors. Connect ohmmeter between ECM connector terminal No. 35 (Green/White wire) and ground. If no continuity is present, system is okay. If continuity is present, repair short circuit to ground in Green/White wire.
5. If DTC 1595 is set, disconnect ECM and change-over valve connectors. Connect voltmeter between ECM connector terminal No. 35 (Green/White wire) and ground. Turn ignition on. If no voltage is present, system is okay. If battery voltage is present, repair short circuit to voltage in Green/White wire.

DTC P1600 & P1601: VOLTAGE SUPPLY

1. If DTC P1601 is set, check voltage regulator. See GENERATOR & REGULATOR article in ELECTRICAL section. If DTC 1600 is set, check battery. Replace as necessary. If battery is okay, disconnect connector X4/2 located under driver's seat. (Scheme 12) Connect voltmeter between fuse panel side of connector X4/2 terminal No. 1 (Red wire) and ground. If battery voltage is not present, go to next step. If battery voltage is present, check voltage regulator and generator. See GENERATOR & REGULATOR article in ELECTRICAL section.
2. Check for open circuit in Red wire circuit between connector X4/2, terminal No. 1 and fuse panel. Check connectors for poor terminal contact. Repair as necessary. Reconnect connector X4/2. Disconnect ECM connector. Connect voltmeter between ECM connector terminal No. 26 (Black/White wire) and ground. If battery voltage is present, check voltage regulator and generator. See GENERATOR & REGULATOR article in ELECTRICAL section. If battery voltage is not present, check for an open circuit in Black/White wire between ECM connector terminal No. 26 and connector X4/2. Repair as necessary.

DTC P1602: VOLTAGE SUPPLY, OPEN CIRCUIT

1. Check battery and replace as necessary. If battery is okay, disconnect connector X4/2 located under driver's seat. (Scheme 12) Connect voltmeter between fuse panel side of connector X4/2 terminal No. 1 (Red wire) and ground. If battery voltage is not present, go to next step. If battery voltage is present, check voltage regulator and generator. See GENERATOR & REGULATOR article in ELECTRICAL section.
2. Check for open circuit in Red wire between connector X4/2 and fuse panel. Repair as necessary. Reconnect connector X4/2. Disconnect ECM connector. Connect voltmeter between ECM connector terminal No. 26 (Black/White wire) and ground. If battery voltage is present, system is okay. If battery voltage is not present, check Black/White wire for an open circuit.

DTC P1610, P1611 & P1614: MIL ACTIVATED EXTERNALLY

Note. Tiptronic control module is located under driver's seat, next to ECM.

1. If DTC P1611 is set, go to step 5). If DTC P1614 is set, go to step 6). If DTC P1610 is set, go to next step.
2. Disconnect Tiptronic (automatic transmission) control unit connector. Connect voltmeter between Tiptronic control unit connector terminals No. 26 (positive - Red wire) and No. 6 (negative - Brown wire), then between terminals No. 55 (positive - Red/White wire) and No. 28 (negative - Brown wire). Turn ignition on. If battery voltage is present, go to next step. If battery voltage is not present, check wiring for an open circuit.
3. Connect Porsche System Tester (9288). Start engine. Select Tiptronic control unit. Select SPEED in ACTUAL VALUES menu. If speed is displayed, go to next step. If speed is not displayed, check for open circuit or short circuit to voltage or ground in Black/Violet wire between Tiptronic control unit terminal No. 43 and ECM terminal No. 80. Repair wiring as necessary.
4. Ensure Tiptronic control unit and ECM connectors are disconnected. Connect ohmmeter between ECM connector terminal No. 12 (Green/Red wire) and Tiptronic control unit connector terminal No. 17. If continuity is present, system is okay. If continuity is not present, check Green/Red wire circuit for an open circuit or poor terminal contact. Repair as necessary.
5. If DTC P1611 is set, disconnect Tiptronic control unit and ECM connectors. Connect ohmmeter between ECM connector terminal No. 12 (Green/Red wire) and ground. If no continuity is present, replace Tiptronic control unit. If continuity is present, repair short circuit to ground in Green/Red wire.
6. If DTC P1614 is set, disconnect Tiptronic control unit and ECM connectors. Turn ignition on. Connect voltmeter between ECM connector terminal No. 12 (Green/Red wire) and ground. If no voltage is present, replace Tiptronic control unit. If voltage is present, repair short circuit to voltage in Green/Red wire.

DTC P1691, P1692 & P1693: MIL

1. Record DTC. If DTC P1692 is set, go to step 4). If DTC P1693 is set, go to step 5). If DTC P1691 is set, go to next step.
2. Disconnect ECM connector. Disconnect connector X4/2 located under driver's seat. (Scheme 12) Connect ohmmeter between ECM connector terminal No. 8 (Black/Violet wire) and ECM side of connector X4/2 terminal No. 8. If continuity is present, go to next step. If continuity is not present, repair open circuit in Black/Violet wire.
3. Disconnect instrument cluster connector II. (Scheme 13) Connect ohmmeter between instrument cluster connector terminal No. 6 (Green/Gray wire) and instrument cluster side of connector X4/2 terminal No. 6. If continuity is present, go to next step. If continuity is not present, repair open circuit in Green/Gray wire.
4. If DTC P1692 is set, disconnect ECM and instrument cluster connector II. (Scheme 13) Connect ohmmeter between ECM connector terminal No. 8 (Black/Violet wire) and ground. If no continuity is present, system is okay. If continuity is present, repair short circuit to ground in Black/Violet wire.
5. If DTC P1693 is set, disconnect ECM and instrument cluster connector II. (Scheme 13) Turn ignition on. Connect voltmeter between ECM connector terminal No. 8 (Black/Violet wire) and ground. If no voltage is present, system is okay. If voltage is present, repair short circuit to voltage in Black/Violet wire.

Scheme 13

DTC P1782: ENGINE ENGAGEMENT, SHORT TO GROUND IN WIRING/ECM

Note. Tiptronic control unit is located under driver's seat.

Disconnect Tiptronic control unit connector. Tiptronic control unit is located next to ECM. Disconnect ECM connector. Connect ohmmeter between ECM connector terminal No. 42 (Brown/Yellow wire) and ground. If no continuity is present, system is okay. If continuity is present, repair short to ground in Brown/Yellow wire.

Poses Online

See also:
• BASIC TESTING
• I - SYSTEM & COMPONENT TESTS
• DTC DEFINITION
• P0101
• P0112
• P0115
• P0122
• P0130
• P0131
• P0132
• P0133
• P0134
• P0136
• P0137
• P0138
• P0139
• P0140
• P0150
• P0151
• P0152
• P0153
• P0154
• P0156
• P0157
• P0158
• P0159
• P0160
• P0300
• P0326
• P0336
• P0341
• P0410
• P0420
• P0441
• P0444
• P0445
• P0501
• P0506
• P0604
• P1102
• P1105
• P1115
• P1117
• P1123
• P1124
• P1140
• P1213
• P1386
• P1411
• P1455
• P1458
• P1501
• P1510
• P1512
• P1541
• P1551
• P1570
• P1593
• P1600
• P1602
• P1610
• P1691
• P1782