Nissan Altima L32. Instruction — part 569

P1421 COLD START CONTROL

EC-1397

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• Crushed intake air passage

• Intake air passage clogging
Is the inspection result normal?

YES

>> GO TO 3.

NO

>> Repair or replace malfunctioning part

3.

CHECK FUEL INJECTION SYSTEM FUNCTION

Perform

EC-1266, "DTC Logic"

for DTC P0171, P0174.

Is the inspection result normal?

YES

>> GO TO 4.

NO

>> Go to

EC-1267, "Diagnosis Procedure"

for DTC P0171, P0174.

4.

PERFORM DTC CONFIRMATION PROCEDURE

1. Turn ignition switch ON.

2. Erase DTC.

3. Perform DTC CONFIRMATION PROCEDURE.

See

EC-1396, "DTC Logic"

.

Is the 1st trip DTC P1421 displayed again?

YES

>> GO TO 5.

NO

>> INSPECTION END

5.

REPLACE ECM

1. Replace ECM.

2. Go to

EC-1051, "ADDITIONAL SERVICE WHEN REPLACING CONTROL UNIT : Special Repair Require-

ment"

.

>> INSPECTION END

EC-1398

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P1550 BATTERY CURRENT SENSOR

P1550 BATTERY CURRENT SENSOR

Description

INFOID:0000000004362256

The power generation voltage variable control enables fuel consumption to be decreased by reducing the

engine load which is caused by the power generation of the generator. The battery current sensor is installed

to the battery cable at the negative terminal. The sensor measures the charging/discharging current of the bat-

tery. Based on the sensor signal, ECM judges whether or not the power generation voltage variable control is

performed. When performing the power generation voltage variable control, ECM calculates the target power

generation voltage based on the sensor signal. And ECM sends the calculated value as the power generation

command value to IPDM E/R. For the details of the power generation voltage variable control, refer to

CHG-6,

"System Description"

.

CAUTION:

Never connect the electrical component or the ground wire directly to the battery terminal. The con-

nection causes the malfunction of the power generation voltage variable control, and then the battery

discharge may occur.

DTC Logic

INFOID:0000000004362257

DTC DETECTION LOGIC

NOTE:

If DTC P1550 is displayed with DTC P0643, first perform the trouble diagnosis for DTC P0643. Refer to

EC-1379, "DTC Logic"

.

DTC CONFIRMATION PROCEDURE

1.

PRECONDITIONING

If DTC Confirmation Procedure has been previously conducted, always perform the following before conduct-

ing the next test.

1. Turn ignition switch OFF and wait at least 10 seconds.

2. Turn ignition switch ON.

3. Turn ignition switch OFF and wait at least 10 seconds.

TESTING CONDITION:

Before performing the following procedure, confirm that battery voltage is more than 8 V at idle.

>> GO TO 2.

2.

PERFORM DTC CONFIRMATION PROCEDURE

1. Start engine and wait at least 10 seconds.

2. Check 1st trip DTC.
Is 1st trip DTC detected?

YES

>> Go to

EC-1398, "Diagnosis Procedure"

.

NO

>> INSPECTION END

Diagnosis Procedure

INFOID:0000000004362258

1.

CHECK GROUND CONNECTION

1. Turn ignition switch OFF.

2. Check ground connection E9. Refer to Ground Inspection in

GI-45, "Circuit Inspection"

.

Is the inspection result normal?

YES

>> GO TO 2.

NO

>> Repair or replace ground connection.

2.

CHECK BATTERY CURRENT SENSOR POWER SUPPLY CIRCUIT

DTC No.

Trouble diagnosis name

DTC detecting condition

Possible cause

P1550

Battery current sensor circuit
range/performance

The output voltage of the battery current
sensor remains within the specified
range while engine is running.

• Harness or connectors

(The sensor circuit is open or shorted.)

• Battery current sensor

P1550 BATTERY CURRENT SENSOR

EC-1399

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1. Disconnect battery current sensor harness connector.

2. Turn ignition switch ON.

3. Check the voltage between battery current sensor harness con-

nector and ground.

Is the inspection result normal?

YES

>> GO TO 3.

NO

>> Repair open circuit, short to ground or short to power in

harness or connectors.

3.

CHECK BATTERY CURRENT SENSOR GROUND CIRCUIT FOR OPEN AND SHORT

1. Turn ignition switch OFF.

2. Disconnect ECM harness connector.

3. Check the continuity between battery current sensor harness connector and ECM harness connector.

4. Also check harness for short to ground and short to power.
Is the inspection result normal?

YES

>> GO TO 4.

NO

>> Repair open circuit, short to ground or short to power in harness or connectors.

4.

CHECK BATTERY CURRENT SENSOR INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT

1. Check the continuity between battery current sensor harness connector and ECM harness connector.

2. Also check harness for short to ground and short to power.
Is the inspection result normal?

YES

>> GO TO 5.

NO

>> Repair open circuit, short to ground or short to power in harness or connectors.

5.

CHECK BATTERY CURRENT SENSOR

Refer to

EC-1399, "Component Inspection"

.

Is the inspection result normal?

YES

>> GO TO 6.

NO

>> Replace battery negative cable assembly.

6.

CHECK INTERMITTENT INCIDENT

Refer to

GI-42, "Intermittent Incident"

.

>> INSPECTION END

Component Inspection

INFOID:0000000004362259

1.

CHECK BATTERY CURRENT SENSOR

1. Turn ignition switch OFF.

2. Reconnect harness connectors disconnected.

Battery current sensor

Ground

Voltage (V)

Connector

Terminal

F5

1

Ground

Approx. 5

JMBIA1602ZZ

Battery current sensor

ECM

Continuity

Connector

Terminal

Connector

Terminal

F5

2

F13

44

Existed

Battery current sensor

ECM

Continuity

Connector

Terminal

Connector

Terminal

F5

3

F13

42

Existed

EC-1400

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[VQ35DE]

P1550 BATTERY CURRENT SENSOR

3. Disconnect battery negative cable (1).
-

: Vehicle front

-

: To body ground

4. Install jumper cable (A) between battery negative terminal and

body ground.

5. Turn ignition switch ON.

6. Check the voltage between ECM harness connector terminals

under the following conditions.

Before measuring the terminal voltage, confirm that the battery is fully charged.
Refer to

PG-3, "How to Handle Battery"

.

Is the inspection result normal?

YES

>> INSPECTION END

NO

>> Replace battery negative cable assembly.

ALBIA0610ZZ

ECM

Voltage (V)

Connector

+

–

Terminal

Terminal

F13

42

(Battery current

sensor signal)

44

(Sensor ground)

Approx. 2.5

JMBIA1879ZZ