Nissan Frontier. Manual - part 457

P1805 BRAKE SWITCH

EC-399

< DTC/CIRCUIT DIAGNOSIS >

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P1805 BRAKE SWITCH

Description

INFOID:0000000009481095

Brake switch signal is applied to the ECM through the stop lamp switch when the brake pedal is depressed.

This signal is used mainly to decrease the engine speed when the vehicle is driving.

On Board Diagnosis Logic

INFOID:0000000009481096

The MIL will not light up for this self-diagnosis.

FAIL-SAFE MODE

When the malfunction is detected, the ECM enters fail-safe mode.

DTC Confirmation Procedure

INFOID:0000000009481097

NOTE:

If DTC Confirmation Procedure has been previously conducted, always turn ignition switch OFF and wait at

least 10 seconds before conducting the next test.

 WITH CONSULT

1. Turn ignition switch ON.
2. Fully depress the brake pedal for at least 5 seconds.
3. Erase the 1st trip DTC with CONSULT.
4. Check 1st trip DTC.
5. If 1st trip DTC is detected, go to 

EC-399, "Diagnosis Procedure"

.

 WITH GST

Follow the procedure “WITH CONSULT” above.

Diagnosis Procedure

INFOID:0000000009481098

1.

CHECK STOP LAMP SWITCH CIRCUIT

1. Turn ignition switch OFF.

2. Check the stop lamp when depressing and releasing the brake pedal.

OK or NG

OK

>> GO TO 4.

NG

>> GO TO 2.

2.

CHECK STOP LAMP SWITCH POWER SUPPLY CIRCUIT 

DTC No.

Trouble diagnosis name

DTC detecting condition

Possible cause

P1805
1805

Brake switch

A brake switch signal is not sent to ECM for ex-
tremely long time while the vehicle is driving.

• Harness or connectors

(Stop lamp switch circuit is open or short-
ed.)

• Stop lamp switch

Engine operating condition in fail-safe mode

ECM controls the electric throttle control actuator by regulating the throttle opening to a small range. Therefore, acceleration will be 
poor.

Vehicle condition

Driving condition

When engine is idling

Normal

When accelerating

Poor acceleration

Brake pedal

Stop lamp

Fully released

Not illuminated

Slightly depressed

Illuminated

EC-400

< DTC/CIRCUIT DIAGNOSIS >

[QR25DE]

P1805 BRAKE SWITCH

1. Disconnect stop lamp switch harness connector.

2. Check voltage between stop lamp switch terminal 1 and ground with CONSULT or tester.

OK or NG

OK

>> GO TO 4.

NG

>> GO TO 3.

3.

DETECT MALFUNCTIONING PART

Check the following.

• 10A fuse (No.20)

• Fuse block (J/B) connector E160 

• Harness for open and short between stop lamp switch and battery

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

4.

CHECK STOP LAMP SWITCH INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT

1. Disconnect ECM harness connector.

2. Disconnect stop lamp switch harness connector.

3. Check harness continuity between ECM terminal 106 and stop lamp switch terminal 2.

Refer to Wiring Diagram.

4. Also check harness for short to ground and short to power.
OK or NG

OK

>> GO TO 5.

NG

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

5.

CHECK STOP LAMP SWITCH 

Refer to 

EC-400, "Component Inspection"

.

OK or NG

OK

>> GO TO 6.

NG

>> Replace stop lamp switch. Refer to 

BR-20, "Exploded View"

.

6.

CHECK INTERMITTENT INCIDENT

Refer to 

GI-42, "Intermittent Incident"

.

>> INSPECTION END

Component Inspection

INFOID:0000000009481099

STOP LAMP SWITCH

1. Disconnect stop lamp switch harness connector.

Voltage: Battery voltage

PBIB2284E

Continuity should exist.

P1805 BRAKE SWITCH

EC-401

< DTC/CIRCUIT DIAGNOSIS >

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2. Check continuity between stop lamp switch terminals 1 and 2 under the following conditions.

If NG, adjust stop lamp switch installation, refer to 

BR-16

, and perform step 2 again.

Conditions

Continuity

Brake pedal: Fully released

Should not exist

Brake pedal: Slightly depressed

Should exist

PBIB2285E

EC-402

< DTC/CIRCUIT DIAGNOSIS >

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P2096, P2097 A/F SENSOR 1

P2096, P2097 A/F SENSOR 1

Component Description

INFOID:0000000009481100

The air fuel ratio (A/F) sensor 1 is a planar one-cell limit current sen-

sor. The sensor element of the A/F sensor 1 is composed an elec-

trode layer, which transports ions. It has a heater in the element.
The sensor is capable of precise measurement   = 1, but also in the

lean and rich range. Together with its control electronics, the sensor
outputs a clear, continuous signal throughout a wide   range.

The exhaust gas components diffuse through the diffusion layer at

the sensor cell. An electrode layer is applied voltage, and this current

relative oxygen density in lean. Also this current relative hydrocar-

bon density in rich.

Therefore, the A/F sensor 1 is able to indicate air fuel ratio by this

electrode layer of current. In addition, a heater is integrated in the

sensor to ensure the required operating temperature of about 800

°C

(1,472

°F).

On Board Diagnosis Logic

INFOID:0000000009481101

DTC Confirmation Procedure

INFOID:0000000009481102

NOTE:

If DTC Confirmation Procedure has been previously conducted, always turn ignition switch OFF and wait at

least 10 seconds before conducting the next test.

TESTING CONDITION:

Before performing the following procedure, confirm that battery voltage is more than 11V at idle.

 WITH CONSULT

1. Start engine and warm it up to normal operating temperature.

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

3. Turn ignition switch ON and select “SELF-LEARNING CONT” in “WORK SUPPORT” mode with CON-

SULT.

4. Clear the self-learning coefficient by touching “CLEAR”.

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

6. Start engine and keep the engine speed between 3,500 and 4,000 rpm for 1 minute under no load.

7. Let engine idle for 1 minute.

8. Keep engine speed between 2,500 and 3,000 rpm for 20 minutes.

9. Check 1st trip DTC.

10. If 1st trip DTC is detected, go to 

EC-403, "Diagnosis Procedure"

.

PBIB3353E

JPBIA5446GB

DTC No.

Trouble diagnosis name

DTC detecting condition

Possible Cause

P2096
2096

Post catalyst fuel tirm sys-
tem too lean bank1

The output voltage computed by ECM from the air 
fuel ratio sensor 1 (A/F sensor 1) signal is shifted 
to the lean side for a specified period.

• Air fuel ratio (A/F) sensor 1
• Air fuel ratio (A/F) sensor 1 heater
• Heated oxygen sensor 2
• Fuel pressure
• Fuel injector
• Intake air leaks
• Exhaust gas leaks

P2097
2097

Post catalyst fuel tirm sys-
tem too rich bank1

The A/F signal computed by ECM from the air fuel 
ratio sensor 1 (A/F sensor 1) signal is shifted to the 
rich side for a specified period.