Nissan Maxima Service and Repair Manual: B257B, B257C ambient sensor

Nissan Maxima Service and Repair Manual / Ventilation, heater & air conditioner / Heater & air conditioning control system / DTC/circuit diagnosis / B257B, B257C ambient sensor

Description

COMPONENT DESCRIPTION

Ambient Sensor

  • The ambient sensor (1) is installed to the front bumper reinforcement.
  • It detects ambient temperature and converts it into a resistance value which is then input into the A/C auto amp.

Nissan Maxima. Ambient Sensor

Ambient Sensor Circuit

Nissan Maxima. Ambient Sensor Circuit

AMBIENT TEMPERATURE INPUT PROCESS

The A/C auto amp. equips a processing circuit for the ambient sensor input. However, when the temperature detected by the ambient sensor increases quickly, the processing circuit retards the A/C auto amp. function. It only allows the A/C auto amp. to recognize an ambient temperature increase of 0.33C (0.6F) per 100 seconds.

As an example, consider stopping for a few minutes after high speed driving. Although the actual ambient temperature has not changed, the temperature detected by the ambient sensor increases. This is because the heat from the engine compartment can radiate to the front bumper area, the location of the ambient sensor.

DTC Logic

DTC DETECTION LOGIC

NOTE:

  • If DTC is displayed along with DTC U1000 or U1010, first diagnose the DTC U1000 or U1010. Refer to HAC- 133, "DTC Logic" or HAC-134, "DTC Logic".
  • If there is an open circuit in the ambient sensor, A/C auto amp. registers extreme cold [-30C (-22F)] and adjusts the temperature control warmer.

DTC CONFIRMATION PROCEDURE

1.CHECK WITH SELF-DIAGNOSIS FUNCTION OF CONSULT

  1. Using CONSULT perform "SELF-DIAGNOSIS RESULTS" of HVAC.
  2. Check if any DTC No. is displayed in the self-diagnosis results.

NOTE:

  • If DTC is displayed along with DTC U1000 or U1010, first diagnose the DTC U1000 or U1010. Refer to HAC- 133, "DTC Logic" or HAC-134, "DTC Logic".
  • If there is an open circuit in the ambient sensor, A/C auto amp. registers extreme cold [-30C (-22F)] and adjusts the temperature control warmer.

Diagnosis Procedure

1.CHECK VOLTAGE BETWEEN AMBIENT SENSOR AND GROUND

  1. Disconnect ambient sensor connector.
  2. Turn ignition switch ON.
  3. Check voltage between ambient sensor harness connector E211 terminal 1 and ground.

Nissan Maxima. CHECK VOLTAGE BETWEEN AMBIENT SENSOR AND GROUND

1 - Ground: Approx. 5V

2.CHECK CONTINUITY BETWEEN AMBIENT SENSOR AND A/C AUTO AMP.

  1. Turn ignition switch OFF.
  2. Disconnect A/C auto amp. connector.
  3. Check continuity between ambient sensor harness connector E211 (A) terminal 2 and A/C auto amp. harness connector M37 (B) terminal 37.

Nissan Maxima. CHECK CONTINUITY BETWEEN AMBIENT SENSOR AND A/C AUTO AMP.

2 - 37: Continuity should exist.

3.CHECK AMBIENT SENSOR

Check ambient sensor.

4.CHECK CONTINUITY BETWEEN AMBIENT SENSOR AND A/C AUTO AMP

  1. Turn ignition switch OFF.
  2. Disconnect A/C auto amp. connector.
  3. Check continuity between ambient sensor harness connector E211 (A) terminal 1 and A/C auto amp. harness connector M37 (B) terminal 35.

Nissan Maxima. CHECK CONTINUITY BETWEEN AMBIENT SENSOR AND A/C AUTO AMP

1 - 35: Continuity should exist.

  1. Check continuity between ambient sensor harness connector E211 (A) terminal 1 and ground.

1 - Ground: Continuity should not exist.

Component Inspection

1.CHECK AMBIENT SENSOR

  1. Turn ignition switch OFF.
  2. Disconnect ambient sensor connector.
  3. Check resistance between ambient sensor terminals.

Nissan Maxima. CHECK AMBIENT SENSOR

    U1010 control unit (CAN)

    B2578, B2579 in-vehicle sensor