Pinpoint Test U: DTC B1317 Or B1318
Climate Control System
Pinpoint Tests
Pinpoint Test U: DTC B1317 or B1318
Refer to Wiring Diagram Set 54, Manual Climate Control System for schematic and connector information. Diagrams By Number
Refer to Wiring Diagram Set 55, Automatic Climate Control System for schematic and connector information. Diagrams By Number
NOTE: DTC B1317, B1318 or B1676 can be set if the vehicle has been recently jump started, the battery has been recently charged or the battery has been discharged. The battery may become discharged due to excessive load(s) on the charging system from aftermarket accessories or if the battery has been left unattended with the accessories on.
NOTE: Carry out a thorough inspection and verification before proceeding with the pinpoint test. Refer to Inspection and Verification. Inspection And Verification
Normal Operation
Under normal operation, the Auxiliary Heater Control Module (AHCM) receives a ground through circuit GD108 (BK/VT)/ZE008 (BK). The AHCM is supplied constant battery voltage through circuit SDC02 (RD)/SDF03 (RD) and ignition switched voltage through circuit CBP37 (WH).
- DTC B1317 (Battery Voltage High) - The module senses when battery voltage is greater than 16 volts.
- DTC B1318 (Battery Voltage Low) - The module senses when battery voltage is less than 9 volts.
This pinpoint test is intended to diagnose the following:
- Fuse(s)
- Wiring, terminals or connectors
- AHCM
PINPOINT TEST U: DTC B1317 OR B1318
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U1 RETRIEVE ALL CMDTCs IN ALL MODULES
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: Self Test - All CMDTCs.
- Is B1317, B1318 or B1676 present in one or more modules AND P0563, P0620, P0625, P0626 or P065B present in the PCM?
Yes
REFER to Charging System for diagnosis of the battery and charging system.
No
GO to U2.
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U2 CHECK BATTERY CONDITION
- Ignition OFF.
- Refer to Battery and carry out the Battery - Condition Test. Pinpoint Tests
- Does the battery pass the condition test?
Yes
If the battery passed the condition test but required a recharge, REFER to Charging System to diagnose the charging system. CLEAR all Continuous Memory Diagnostic Trouble Codes (CMDTCs). TEST the system for normal operation.
If the battery passed the condition test and did not require a recharge, GO to U3.
No
INSTALL a new battery. CLEAR all CMDTCs. TEST the system for normal operation.
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U3 CHECK THE CHARGING SYSTEM VOLTAGE
NOTE: Do not allow the engine rpm to increase above 2,000 rpm while performing this step or the generator may self excite and result in default charging system output voltage. If engine rpm has gone above 2,000 rpm, shut the vehicle OFF and restart the engine before performing this step.
- Start the engine.
- Measure the voltage of the battery:
- For DTC B1317, turn off all accessories and run the engine at 1,500 rpm for a minimum of 2 minutes.
- For DTC B1318, turn on headlights and HVAC fan on high and run engine at 1,500 rpm for a minimum of 2 minutes.
- Is the battery voltage between 13-15.2 volts?
Yes
GO to U4.
No
REFER to Charging System to diagnose the charging system. CLEAR all CMDTCs. TEST the system for normal operation.
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U4 CHECK FOR VOLTAGE BY MONITORING THE SYSTEM BATTERY VOLTAGE (BATT_V) AHCM PID
- Enter the following diagnostic mode on the scan tool: BATT_V AHCM PID.
- With the engine running, monitor the battery voltage BATT_V AHCM PID.
- Is the battery voltage less than 9 or greater than 15.5 volts?
Yes
If voltage is less than 9 volts, GO to U5.
If voltage is greater than 15.5 volts, INSTALL a new AHCM. CLEAR all CMDTCs. REPEAT the self-test.
No
GO to U7.
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U5 CHECK CIRCUIT CBP37 (WH) FOR VOLTAGE
- Ignition OFF.
- Disconnect: AHCM C2463c.
- Ignition ON.
- Measure the voltage between ground and AHCM C2463c-1, circuit CBP37 (WH), harness side.
- Is the voltage greater 10 volts?
Yes
GO to U6.
No
VERIFY Smart Junction Box (SJB) fuse 37 (10A) is OK. If OK, REPAIR circuit CBP37 (WH) for an open. TEST the system for normal operation.
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U6 CHECK CIRCUIT GD108 (BK/VT)/ZE008 (BK) FOR AN OPEN
- Ignition OFF.
- Disconnect: AHCM C2463a.
- Measure the resistance between ground and AHCM C2463b-1, circuit ZE008 (BK), harness side.
- Is the resistance less than 5 ohms?
Yes
GO to U7.
No
REPAIR circuit GD108 (BK/VT)/ZE008 (BK) for an open. TEST the system for normal operation.
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U7 CHECK FOR CORRECT AHCM OPERATION
- Ignition OFF.
- Check the harness and component side connectors for:
- corrosion.
- pushed-out terminals.
- damaged terminals.
- Connect and correctly seat all the AHCM connectors.
- Operate the system and determine if the concern is still present.
- Is the concern still present?
Yes
INSTALL a new AHCM. CLEAR all CMDTCs. REPEAT the self-test. TEST the system for normal operation.
No
The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. CLEAR all CMDTCs. REPEAT the self-test. TEST the system for normal operation.
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