Inspection & Verification
- Verify the customer's concern by operating the climate control system to duplicate the condition.
- Inspect to determine if one of the following mechanical or electrical concerns apply. See «VISUAL INSPECTION CHART»(ref-207561-S10430272672005113000000) . VISUAL INSPECTION CHART Mechanical Electrical Loose, missing or damaged A/C compressor drive belt Loose or disconnected A/C clutch Broken or leaking refrigerant lines Obstructed in-vehicle temperature sensor Disconnected in-vehicle temperature aspirator hose A/C registers are not working (open/close) Front floor ducts not in place Incorrectly installed in-vehicle temperature sensor Incorrectly installed ambient air temperature sensor Fuse(s) Blower motor inoperative A/C compressor inoperative Circuit short/open. Disconnected, loose fitting, or incorrectly installed electrical connectors and pins Cooling fan inoperative Relays not functional or not installed
- As pinpoint tests and measurements are being carried out, be sure to inspect for any disconnected, loose-fitting, or incorrectly installed component, module and in-line electrical connectors and pins.
- If the inspection reveals obvious concerns that can be readily identified, repair as necessary.
- If the concern remains after the inspection, connect the scan tool to the data link connector (DLC) located beneath the instrument panel and select the vehicle to be tested from the scan tool menu. If the vehicle selection cannot be entered: Check that the program card is correctly installed. Check the connections to the vehicle. Check the ignition switch position. Check that the battery voltage is greater than 9V. If the scan tool still does not allow the vehicle selection to be entered, refer to the scan tool manufacturer's manual.
- Carry out the Data Link Diagnostic Test using the scan tool. If the scan tool responds with: SCP+, SCP- or UBP circuits fault = ALL MODULE NO RESPONSE/NOT EQUIPPED, go to Module Communication Network Diagnostics to diagnose the network concern. If the powertrain control module (PCM) is not listed for a communication concern, turn the A/C controls to OFF and execute the self-test diagnostics for the PCM. If the DATC module is not listed for a communication concern, execute the self-test diagnostics for the DATC module.
- If any PCM or DATC DTCs are retrieved, and are related to the concern, go to the «POWERTRAIN CONTROL MODULE (PCM) DIAGNOSTIC TROUBLE CODE (DTC) INDEX»(ref-207561-S17276277902005113000000) or «DUAL ELECTRONIC AUTOMATIC TEMPERATURE CONTROL (DATC) MODULE DIAGNOSTIC TROUBLE CODE (DTC) INDEX»(ref-207561-S32794440092005113000000) to continue the diagnostics.
- If no DTCs related to the concern are retrieved, GO to «SYMPTOM CHART»(ref-207561-S15008383782005113000000) to continue the diagnostics.
- If the DATC module cannot be accessed by the scan tool, Go «TO PINPOINT TEST A»(ref-207561-S30183804712005113000000) .
Dual Electronic Automatic Temperature Control (DATC) Module Diagnostic Trouble Codes - DTCs
If using the scan tool or front panel diagnostics to check for DATC DTCs
- Check continuous DTCs.
- Run DATC self-test. Refer to «FRONT PANEL DATC MODULE SELF-TEST (ON-DEMAND DIAGNOSTIC TROUBLE CODES - DTCS)»(ref-207561-S35093432932005113000000) . General Information: If the DTC is continuous only and does not appear in the self-test, this indicates an intermittent fault condition, such as a poor wiring connection or a loose terminal. If the DATC does not appear after running the self-test it may also indicate that the DTC may no longer exist. If the DTC is continuous and appears in the self-test, this indicates a hard fault. A hard fault suggests a permanent wiring failure, disconnected connector or component failure.
Front Panel DATC Module Self-Test (On-Demand Diagnostic Trouble Codes - DTCs)
On-demand DTCs are those that are reported by an ECU when a failure is detected while executing a diagnostic test. For the DATC module this means that all faults (hard) that occur while the module is conducting a self-test shall be reported as an on-demand DTC.
- The DATC module self-test will not detect concerns associated with data link messages such as engine coolant temperature or vehicle speed signals. The scan tool must be used to retrieve these concerns.
- The vehicle interior temperature should be between 0-32°C (32-90°F) when carrying out the self-test. If the temperatures are not within the specified ranges, false temperature sensor DTCs may be displayed.
The DATC module self-test through the front panel display
- Can be initiated at any time. Normal operation of the system stops when the self-test is activated.
- Is entered by pressing the OFF and DEFROST buttons simultaneously and then pressing the AUTO button within two seconds. Record all DTCs displayed.
- Concludes by reporting all on-demand DTCs. Follow the diagnostics procedure given under ACTION in the DTC index for each DTC given.
- Reports individual on-demand DTCs as four-digit DTCs (less the alpha character).
- Will calibrate all the mode doors and check all analog inputs. The DATC module will only report on-demand (hard) faults that occurred while the DATC module was conducting its self-test.
- Will light all control panel display segments if no faults are detected.
- Will report individual on-demand DTCs without the °C symbol lit.
To exit the self-test, press the defrost button. This will clear all on-demand codes from the DATC module memory. If no button is pushed, DTCs will continue to be displayed.
Upon exit from the self-test the DATC module returns to operational status. The DATC module executes a hard (cold boot) reset which places the DATC system in the OFF mode.
If a condition exists but no DTCs appear during the self-test, GO to SYMPTOM CHART Condition: The DATC System Is Inoperative, Intermittent or Incorrect Operation.
Always exit the self-test before powering the system down (system turned OFF).
Front Panel DATC Module Display - Retrieve Continuous Diagnostic Trouble Codes (DTCS)
Continuous DTCs are fault codes recorded by the DATC module which have occurred during normal operation. For the DATC module this means that all faults (intermittent or hard) that occur while the module is in an operational state shall be reported as a continuous DTC.
- To retrieve continuous DTCs, press the OFF and DEFROST buttons simultaneously, followed by pressing the RECIRC button within two seconds.
- The DATC module will report all continuous DTCs to the vacuum fluorescent (VF) display.
- The DATC module will not carry out a self-test; it will only display continuous faults codes which are stored in memory.
- All VF display segments will light if no faults are detected.
- Individual continuous DTCs will be reported with the °C symbol lit.
- DTCs shall be reported as a four-digit DTC (less the alpha character).
- Pressing the front defrost button will exit the retrieve continuous DTCs mode and clear all continuous DTCs from DATC module memory.
- Pressing any other button (other than DEFROST) will exit the retrieve continuous DTCs mode and maintain all continuous DTCs in DATC module memory.
- Upon exit from the retrieve continuous DTCs mode the DATC module returns to operational status. The DATC module executes a hard (cold boot) reset which places the DATC system in the OFF mode.
Diagnostic Trouble Code Index
| DTC | Description | Action |
|---|---|---|
| P1460 | WOT A/C cutout internal driver malfunction | REFER to INTRODUCTION article. |
| P1461 | A/C pressure sensor circuit high input | REFER to INTRODUCTION article. |
| P1462 | A/C pressure sensor circuit low input | REFER to INTRODUCTION article. |
| P1463 | A/C pressure sensor insufficient pressure variation | REFER to INTRODUCTION article. |
| P1469 | Low A/C cycling period | REFER to INTRODUCTION article. |
| P1474 | Low speed fan internal driver failure | REFER to INTRODUCTION article. |
| P1479 | High speed fan internal driver failure | REFER to INTRODUCTION article. |
| P1464 | A/C demand out of self-test range | REFER to INTRODUCTION article. |
POWERTRAIN CONTROL MODULE (PCM) DIAGNOSTIC TROUBLE CODE (DTC) INDEX
| DTC | Run-Time (Intermittent) Faults or Self-Test (Hard) Faults | Description | Action to Take |
|---|---|---|---|
| B1242 | 1242 | Air inlet door actuator circuit failure | Go To PINPOINT TEST C . |
| B1251 | 1251 | In-vehicle temperature sensor circuit open | Go To PINPOINT TEST D: DTC B1251 OR DTC 1253 - A/C IN-VEHICLE TEMPERATURE SENSOR OPEN CIRCUIT OR SHORT TO GROUND . |
| B1253 | 1253 | In-vehicle temperature sensor circuit short to ground | Go To PINPOINT TEST D: DTC B1251 OR DTC 1253 - A/C IN-VEHICLE TEMPERATURE SENSOR OPEN CIRCUIT OR SHORT TO GROUND . |
| B1255 | 1255 | Ambient air temperature sensor open | Go To PINPOINT TEST F: DTC B1255 OR DTC B1257 - A/C AMBIENT TEMPERATURE SENSOR OPEN CIRCUIT OR SHORT TO GROUND . |
| B1257 | 1257 | Ambient air temperature sensor short to ground | Go To PINPOINT TEST F: DTC B1255 OR DTC B1257 - A/C AMBIENT TEMPERATURE SENSOR OPEN CIRCUIT OR SHORT TO GROUND . |
| B1259 | 1259 | A/C solar radiation sensor open circuit | Go To PINPOINT TEST G: DTC B1259 OR DTC B1261 - SOLAR RADIATION SENSOR OPEN CIRCUIT OR SHORT TO GROUND . |
| B1261 | 1261 | A/C solar radiation sensor circuit short to ground | Go To PINPOINT TEST G: DTC B1259 OR DTC B1261 - SOLAR RADIATION SENSOR OPEN CIRCUIT OR SHORT TO GROUND . |
| B1262 | 1262 | Defrost door actuator circuit failure | Go To PINPOINT TEST C . |
| B1263 | 1263 | Panel door actuator circuit failure | Go To PINPOINT TEST C . |
| B1264 | 1264 | Floor door actuator circuit failure | Go To PINPOINT TEST C . |
| B1265 | 1265 | Cold air bypass door actuator circuit failure | INSPECT the vehicle for the presence of a cold air bypass door actuator. If a cold air bypass door actuator is present, Go To PINPOINT TEST C . If a cold air bypass door actuator is not present, ignore DTC B1265. |
| B1342 | 1342 | ECU defective | INSTALL a new DATC module. |
| B1676 | 1676 | Battery voltage out of range | |
| B1946 | 1946 | Evaporator discharge temperature sensor open circuit | Go To PINPOINT TEST E: DTC B1946, B1947, B1966, B1967, B2428 OR B2429 - EVAPORATOR OR HEATER CORE DISCHARGE AIR TEMPERATURE SENSOR CIRCUIT OPEN OR SHORT TO GROUND . |
| B1947 | 1947 | Evaporator discharge temperature sensor circuit short to ground | Go To PINPOINT TEST E: DTC B1946, B1947, B1966, B1967, B2428 OR B2429 - EVAPORATOR OR HEATER CORE DISCHARGE AIR TEMPERATURE SENSOR CIRCUIT OPEN OR SHORT TO GROUND . |
| B1966 | 1966 | Driver heater core discharge temperature sensor open circuit | Go To PINPOINT TEST E: DTC B1946, B1947, B1966, B1967, B2428 OR B2429 - EVAPORATOR OR HEATER CORE DISCHARGE AIR TEMPERATURE SENSOR CIRCUIT OPEN OR SHORT TO GROUND . |
| B1967 | 1967 | Driver heater core discharge temperature sensor short circuit | Go To PINPOINT TEST E: DTC B1946, B1947, B1966, B1967, B2428 OR B2429 - EVAPORATOR OR HEATER CORE DISCHARGE AIR TEMPERATURE SENSOR CIRCUIT OPEN OR SHORT TO GROUND . |
| B2428 | 2428 | Passenger heater core discharge temperature sensor open circuit | Go To PINPOINT TEST E: DTC B1946, B1947, B1966, B1967, B2428 OR B2429 - EVAPORATOR OR HEATER CORE DISCHARGE AIR TEMPERATURE SENSOR CIRCUIT OPEN OR SHORT TO GROUND . |
| B2429 | 2429 | Passenger heater core discharge temperature sensor short circuit | Go To PINPOINT TEST E: DTC B1946, B1947, B1966, B1967, B2428 OR B2429 - EVAPORATOR OR HEATER CORE DISCHARGE AIR TEMPERATURE SENSOR CIRCUIT OPEN OR SHORT TO GROUND . |
| B2477 | 2477 | Module configuration failure | RECONFIGURE the DATC module. |
| B2797 | 2797 | Driver coolant control valve open circuit | Go To PINPOINT TEST J: FULL HEAT ONLY IN ALL MODES . |
| B2798 | 2798 | Driver coolant control valve circuit short to ground | Go To PINPOINT TEST H: INSUFFICIENT, ERRATIC OR NO HEAT . |
| B2799 | 2799 | Passenger coolant control valve open circuit | Go To PINPOINT TEST J: FULL HEAT ONLY IN ALL MODES . |
| B2800 | 2800 | Passenger coolant control valve circuit short to ground | Go To PINPOINT TEST H: INSUFFICIENT, ERRATIC OR NO HEAT . |
| U1041 | 5041 | SCP invalid or missing data for function read vehicle speed | REFER to INTRODUCTION article. |
| U1073 | 5073 | SCP invalid or missing data for engine coolant | REFER to INTRODUCTION article. |
| U1027 | 5027 | SCP invalid or missing data for engine RPM | REFER to INTRODUCTION article. |
| U1178 | 5178 | SCP invalid or missing data for voice command | This code will only appear if the vehicle is equipped with voice command. |
| U1222 | 5222 | SCP invalid or missing data for interior lamps |
DUAL ELECTRONIC AUTOMATIC TEMPERATURE CONTROL (DATC) MODULE DIAGNOSTIC TROUBLE CODE (DTC) INDEX
Symptom Chart
| Condition | Possible Sources | Action |
|---|---|---|
| No communication with the dual automatic temperature control (DATC) module | Fuse. Circuitry. DATC module communication network. DATC module not connected. | Go To PINPOINT TEST A . |
| The DATC system is inoperative, intermittent or incorrect operation | Circuitry. Input sensors or erratic input signals. Charging system. In-vehicle temperature control sensor hose and elbow (No aspiration). Air trapped in heater coolant circuits. Missing or invalid SCP messages. | Go To PINPOINT TEST B: THE DATC SYSTEM IS INOPERATIVE, INTERMITTENT OR INCORRECT OPERATION . |
| Incorrect/erratic direction of airflow from outlets | Circuitry. Door actuator. Mode door binding or stuck. DATC module. Door actuator arm not connected to the door crank. | Go To PINPOINT TEST C . |
| Insufficient, erratic, or no heat | Circuitry. Low engine coolant level. Air trapped in heater coolant circuit. Plugged or partially plugged heater core. Bypass door actuator binding or stuck open. Coolant control valve. DATC module. Engine coolant thermostat. | Go To PINPOINT TEST H: INSUFFICIENT, ERRATIC OR NO HEAT . |
| Insufficient heat during engine idle - 3.9L Engine | Low engine coolant level. Cold engine. Bypass door actuator binding or stuck. Auxiliary coolant pump (V8 only). Engine coolant thermostat. | Go To PINPOINT TEST I: INSUFFICIENT HEAT DURING ENGINE IDLE - 3.9 L ENGINE . |
| Full heat only in all modes | Fuse(s). Circuitry. Coolant control valve. DATC module. | Go To PINPOINT TEST J: FULL HEAT ONLY IN ALL MODES . |
| The dual temperature control is inoperative/does not operate correctly | Circuitry. DATC module configuration. DATC module. Coolant control valve. Low coolant level. Air trapped in coolant circuit. Incorrect heater hose connections. Air temperature sensors. | Go To PINPOINT TEST K: THE DUAL TEMPERATURE CONTROL IS INOPERATIVE/DOES NOT OPERATE CORRECTLY . |
| The air conditioning (A/C) is inoperative/does not operate correctly | Fuse(s). Circuitry. A/C clutch relay. Evaporator discharge temperature sensor. A/C system discharged or low charge. A/C pressure transducer. DATC module. PCM. | Go To PINPOINT TEST L: THE A/C DOES NOT OPERATE/DOES NOT OPERATE CORRECTLY . |
| The air conditioning (A/C) is always on | Circuitry. A/C control. A/C clutch relay. Evaporator air discharge sensor. DATC module. PCM | Go To PINPOINT TEST M: THE AIR CONDITIONING (A/C) IS ALWAYS ON . |
| The blower motor is inoperative | Circuitry. Blower motor. Blower motor speed control. Blower motor relay. DATC module. | Go To PINPOINT TEST N: THE BLOWER MOTOR IS INOPERATIVE . |
| The blower motor does not operate correctly | Blower motor speed control. DATC module. Circuitry. | Go To PINPOINT TEST O: THE BLOWER MOTOR DOES NOT OPERATE CORRECTLY . |
| The temperature set point does not repeat after turning the ignition switch off | Fuse. Circuitry. DATC module. | CHECK circuit 29-FA10 (OG/GN) for an open and repair as necessary. If okay, INSTALL a new DATC module. |
| The temperature display will not switch between Celsius and Fahrenheit | DATC module. | INSTALL a new DATC module. TEST the system for normal operation. |
SYMPTOM CHART
PINPOINT TEST E: DTC B1946, B1947, B1966, B1967, B2428 or B2429 - EVAPORATOR OR HEATER CORE DISCHARGE AIR TEMPERATURE SENSOR CIRCUIT OPEN OR SHORT TO GROUND
Note. Evaporator core, driver side heater core and passenger side heater core discharge air temperature sensors have the same diagnostic procedure.
Scheme 11
Scheme 12
Scheme 13
Scheme 14
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Scheme 16
- E1 CHECK THE SENSOR RESISTANCE Key in OFF position. Disconnect: Sensor. Refer to the table and disconnect the sensor associated with the DTCs recorded from the DATC module self-test. See «CHECKING SENSOR RESISTANCE PIN CIRCUIT REFERENCE»(ref-207561-S40991774642005113000000) . CHECKING SENSOR RESISTANCE PIN CIRCUIT REFERENCE Sensor Condition DTC Connector EVAP air discharge Open B1946 C296 EVAP air discharge Short B1947 C296 Driver air Open B1966 C255 Driver air Short B1967 C255 Passenger air Open B2428 C235 Passenger air Short B2429 C235 Measure the resistance between sensor terminals. Is the resistance within the specified values for these temperature ranges: 10-20°C (50-68°F) 37,000-58,000 ohms; 20-30°C (68-86°F) 24,000-37,000 ohms; 30-40°C (86-104°F) 16,000-24,000 ohms? Yes : GO to E2. No : INSTALL a new sensor. TEST the system for normal operation.
- E2 CHECK THE DATC SENSOR OUTPUT VOLTAGE Key in ON position. Refer to the following chart and measure the voltage between temperature sensor harness side circuits. CONNECTOR CIRCUIT REFERENCE Connector Circuit Circuit C296 8-FA44 (WH/RD) 9-FA44 (BN/RD) C255 8-FA51 (WH/BK) 9-FA51 (BN/YE) C235 8-FA47 (WH/GN) 9-FA47 (BN/GN) Is the voltage between 4.7 and 5.1 volts? Yes : INSTALL a new DATC module. TEST the system for normal operation. No : If DTC B1946, B1966or B2428 is present, GO to E3. If DTC B1947, B1967or B2429 is present, GO to E5.
- E3 CHECK THE REFERENCE CIRCUIT FOR AN OPEN Key in OFF position. Disconnect: DATC Module C228a. Refer to the following chart and measure the resistance of the reference circuit between DATC module C228a and the sensor connector. SENSOR CONNECTOR CIRCUIT REFERENCE Sensor Connector Circuit DATC C228a Pin Veep Discharge C296 8-FA44 (WH/RD) 10 Passenger Side C255 8-FA51 (WH/BK) 6 Driver C235 8-FA47 (WH/GN) 18 Is the resistance less than 5 ohms? Yes : GO to E4. No : REPAIR the affected circuit. TEST the system for normal operation.
- E4 CHECK RETURN CIRCUIT FOR AN OPEN Refer to the following chart and measure the resistance of the return circuit between sensor and DATC module C228a for an open. See «SENSOR CONNECTOR CIRCUIT REFERENCE»(ref-207561-S14620686732005113000000) . SENSOR CONNECTOR CIRCUIT REFERENCE Sensor Connector DATC Module C228a Pin Circuit Evap/C296 16 9-FA44 (BN/RD) Passenger/C255 19 9-FA51 (BN/YE) Driver/C235 19 9-FA47 (BN/GN) Is the resistance less than 5 ohms? Yes : INSTALL a new DATC module. TEST the system for normal operation. No : REPAIR the affected circuit. TEST the system for normal operation.
- E5 CHECK THE REFERENCE CIRCUIT FOR A SHORT TO GROUND Key in OFF position. Disconnect: DATC Module C228a. Refer to the following chart and measure the resistance of the sensor reference circuit between DATC module C228a and ground. TEMPERATURE SENSOR CIRCUIT REFERENCE Temperature Sensor DATC Module C228a Pin Circuit Evaporator Core 10 8-FA44 (WH/RD) Passenger 6 8-FA51 (WH/BK) Driver 18 8-FA47 (WH/GN) Is the resistance greater than 10,000 ohms? Yes : GO to E6. No : REPAIR the affected circuit. TEST the system for normal operation.
- E6 CHECK THE REFERENCE CIRCUITS FOR A SHORT TO THE RETURN CIRCUITS Refer to the following chart and measure the resistance between temperature sensor harness side circuits. See «CONNECTOR CIRCUIT REFERENCE»(ref-207561-S35351141182005113000000) . CONNECTOR CIRCUIT REFERENCE Connector Circuit Circuit C296 8-FA44 (WH/RD) 9-FA44 (BN/RD) C255 8-FA51 (WH/BK) 9-FA51 (BN/YE) C235 8-FA47 (WH/GN) 9-FA47 (BN/GN) Is the resistance greater than 10,000 ohms? Yes : INSTALL a new DATC module. TEST the system for normal operation. No : REPAIR the reference circuit for a short to the return circuit. TEST the system for normal operation.
PINPOINT TEST L: THE A/C DOES NOT OPERATE/DOES NOT OPERATE CORRECTLY
Note. Before carrying out the following test, diagnose any PCM DTCs.
Note. Before carrying out the following test, make sure the A/C system pressure is above 290 kPa (42 psi). If the pressure is below 290 kPa (42 psi), refer to FLUORESCENT DYE LEAK DETECTION .
Note. The ambient temperature must be above 0°C (32°F ) to permit the A/C compressor to operate.
Scheme 17
Scheme 18
Scheme 19
Scheme 20
Scheme 21
Scheme 22
Scheme 23
Scheme 24
- L1 CHECK THE A/C PRESSURE PCM PID Key in ON position. Enter the following diagnostic mode on the diagnostic tool: A/C Pressure PCM PID. With the manifold gauge set connected, compare the pressure readings of the manifold gauge set and the A/C pressure PID. Are the pressure values of the manifold gauge set and the A/C pressure PID similar? Yes : GO to L2. No : INSTALL a new A/C pressure transducer. TEST the system for normal operation.
- L2 CHECK THE A/C EVAPORATOR TEMPERATURE PID Allow the vehicle exterior and interior to stabilize to an ambient temperature above 16°C (60°F). Enter the following diagnostic mode on the diagnostic tool: A/C Evaporator Discharge Temperature PCM PID. Does the A/C evaporator discharge temperature PID read similar to the ambient temperature? Yes : GO to L3. No : INSTALL a new A/C evaporator discharge temperature sensor. TEST the system for normal operation.
- L3 VERIFY CUSTOMER COMPLAINT Make sure the engine is at operating temperature. Select panel and A/C modes. Is full heat present in all temperature settings? Yes : Go To «PINPOINT TEST J: FULL HEAT ONLY IN ALL MODES»(ref-207561-S03883857102005113000000) . No : GO to L4.
- L4 CARRY OUT THE PCM AND DATC MODULE SELF-TESTS Enter the following diagnostic mode on the diagnostic tool: PCM Self Test. Key in ON position. Carry out the PCM self-test. Record any DTCs displayed. Carry out the DATC module self-test and retrieve continuous DTCs. Refer to «CLIMATE CONTROL SYSTEM»(ref-207561-S19062633142005113000000) . Record the DTCs displayed, if any. Were any DTCs displayed? Yes : REFER to «POWERTRAIN CONTROL MODULE (PCM) DIAGNOSTIC TROUBLE CODE (DTC) INDEX»(ref-207561-S17276277902005113000000) or «DUAL ELECTRONIC AUTOMATIC TEMPERATURE CONTROL (DATC) MODULE DIAGNOSTIC TROUBLE CODE (DTC) INDEX»(ref-207561-S32794440092005113000000) . CARRY OUT the necessary diagnosis and REPAIR as necessary. No : GO to L5.
- L5 CHECK PID WACF WITH THE A/C ON NOTE: When PCM PID WACF is YES, this is the same fault as DTC P1460. Key in ON position. With the engine running, press the DATC PANEL and A/C override button. Make sure the A/C indicator LED is on. Enter the following diagnostic mode on the diagnostic tool: PCM PID WACF. Does the PCM PID WACF read YES? Yes : REFER to INTRODUCTION article to continue the diagnosis. No : GO to L6.
- L6 CHECK PID ACCS WITH THE A/C ON Make sure PID EXT FT2 reading is greater than 0°C (32°F). Make sure that the PID ACPEVAP reading is greater than 2°C (35°F). Make sure the engine is at idle. Press the DATC PANEL and the A/C override buttons. Make sure the A/C indicator LED is on. Enter the following diagnostic mode on the diagnostic tool: PCM PID ACCS. Does the PCM PID ACCS read ON? Yes : GO to L7. No : INSTALL a new DATC module. TEST the system for normal operation.
- L7 CHECK PID WAC WITH THE A/C ON Press the DATC PANEL and the A/C override button. Make sure the A/C indicator LED is on. Enter the following diagnostic mode on the diagnostic tool: PCM PID WAC. Does the PID WAC read ON? Yes : GO to L8. No : REFER to INTRODUCTION article to continue the diagnosis.
- L8 CHECK THE REFRIGERANT SYSTEM PRESSURE Key in OFF position. Connect the manifold set to the service ports. Refer to «MANIFOLD GAUGE SET CONNECTION»(ref-207561-S42669147032005113000000) . Is the pressure between 345 kPa (50 psi) and 1,724 kPa (250 psi)? Yes : GO to L9. No : CHECK the system for refrigerant system leaks. REPAIR as necessary. TEST the system for normal operation.
- L9 CHECK FOR POWER TO THE A/C RELAY Key in OFF position. Disconnect: A/C Clutch Relay. Key in ON position. Measure the voltage between A/C clutch relay C1008 pin 3, circuit 30-FA79 (RD/OG), harness side and ground. Is the voltage greater than 10 volts? Yes : GO to L10. No : REPAIR circuit 30-FA79 (RD) for an open. TEST the system for normal operation.
- L10 CHECK CIRCUIT 15S-FA79 (GN/RD) FOR VOLTAGE Measure the voltage between A/C clutch relay C1008 pin 1, circuit 15S-FA79 (GN/RD), harness side and ground. Is the voltage greater than 10 volts? Yes : GO to L11. No : REPAIR circuit 15S-FA79 (GN/RD) for an open. TEST the system for normal operation.
- L11 CHECK CIRCUIT 30-FA79 (RD) FOR A SHORT TO GROUND Press the DEFROST override button on the DATC module. Measure the voltage between A/C clutch relay C1008 pin 1, circuit 15S-FA79 (GN/RD) and pin 2, circuit 91S-FA79 (BN/BU). Is the voltage greater than 10 volts? Yes : GO to L14 . No : GO to L12.
- L12 CHECK CIRCUIT 91S-FA79 (BN/BU) FOR AN OPEN Key in OFF position. Disconnect: PCM C175. Measure the resistance between the A/C control relay socket pin 2, circuit 91S-FA79 (BN/BU) and the PCM C175a-9 circuit 91S-FA79 (BN/BU). Is the resistance less than 5 ohms? Yes : GO to L13. No : REPAIR circuit 91S-FA79 (BN/BU) for an open. TEST the system for normal operation.
- L13 CHECK CIRCUIT 91S-FA79 (BN/BU) FOR A SHORT TO VOLTAGE Key in ON position. Measure the voltage between the A/C control relay socket pin 2, circuit 91S-FA79 (BN/BU) and the ground. Is voltage present? Yes : REPAIR circuit 91S-FA79 (BN/BU). CLEAR the DTCs. TEST the system for normal operation. No : INSTALL a new PCM. TEST the system for normal operation.
- L14 CHECK THE A/C CLUTCH INPUT Key in OFF position. Connect: A/C Clutch Relay. Disconnect: A/C Clutch Field Coil C100. Key in ON position. With the engine running, measure the voltage between A/C clutch field coil C100-2, circuit 15S-FA6 (GN/YE), harness side and ground. Is the voltage greater than 10 volts? Yes : GO to L16 . No : GO to L15.
- L15 CHECK CIRCUIT 15S-FA6 (GN/YE) FOR AN OPEN Key in OFF position. Measure the resistance between A/C clutch C100-2, circuit 15S-FA6 (GN/YE) and A/C clutch relay C1008 pin 5, circuit 15S-FA6 (GN/YE). Is the resistance 5 ohms or less? Yes : INSTALL a new A/C clutch relay. TEST the system for normal operation. No : REPAIR circuit 15S-FA6 (GN/YE) for an open. TEST the system for normal operation.
- L16 CHECK THE A/C CLUTCH GROUND CIRCUIT FOR AN OPEN Key in OFF position. Measure the resistance between A/C clutch C100-1, circuit 31-FA6 (BK/YE), harness side and ground. Is the resistance 5 ohms or less? Yes : GO to L17. No : REPAIR circuit 31-FA6 (BK/YE). TEST the system for normal operation.
- L17 CHECK THE CLUTCH AIR GAP Measure the A/C compressor clutch air gap at three equally spaced locations between the clutch hub and the A/C compressor clutch pulley. Is the A/C compressor clutch air gap greater than 0.75 mm (0.030 in)? Yes : ADJUST the A/C compressor clutch field coil. TEST the system for normal operation. No : INSTALL a new A/C compressor clutch field coil. TEST the system for normal operation.
Heater Core - Pressure Test
Use the Pressure Test Kit to carry out the pressure test.
Scheme 25
- Drain the coolant from the cooling system.
- Disconnect the heater hoses from the heater core.
- Install a short piece of heater hose, approximately 101 mm (4 inches) long on each heater core tube.
- Fill the heater core and heater hoses with water and install the two plugs BT-7422-B and the adapter BT-7422-A from the Pressure Test Kit. Secure the heater hoses, plug and adapter with hose clamps.
- Attach the pump and gauge assembly from the Pressure Test Kit to the adapter.
- Close the bleed valve at the base of the gauge. Pump 138 kPa (20 psi) of air pressure into the heater core.
- Observe the pressure gauge for a minimum of three minutes.
- If the pressure drops, check the heater hose connections to the core tubes for leaks. If the heater hoses do not leak, remove the heater core from the vehicle and carry out the bench test.
Scheme 26
- Remove the heater core from the vehicle.
- Drain all of the coolant from the heater core.
- Connect the 101 mm (4 inch) test heater hoses with plug and adapter to the core tubes. Then connect the Pressure Test Kit to the adapter.
- Apply 138 kPa (20 psi) of air pressure to the heater core. Submerge the heater core in water.
- If a leak is observed, install a new heater core.
Evaporator/Condenser Core - On-Vehicle Leak Test
- Discharge and recover the refrigerant. For additional information, refer to «AIR CONDITIONING (A/C) SYSTEM RECOVERY, EVACUATION AND CHARGING»(ref-207561-S32152738792005113000000) .
- Disconnect the suspect evaporator core or condenser core from the A/C system.
- Clean the manifold fittings.
- Connect the appropriate test fittings from the Set, A/C Fittings to the condenser core tube connections.
- Connect the Vacuum Check Fitting, TXV to the thermostatic expansion valve.
- Connect the red and blue hoses from the R-134a Manifold Gauge Set to the test fittings on the evaporator core or condenser core. Connect the yellow hose to a known good vacuum pump.
- Open both gauge set valves and start the vacuum pump. Allow the vacuum pump to operate for a minimum of 45 minutes after the gauge set low pressure gauge indicates 101 kPa (30 in-Hg). The 45-minute evacuation is necessary to remove any refrigerant from oil left in the evaporator core or condenser core. If the refrigerant is not completely removed from the oil, outgassing will degrade the vacuum and appear as a refrigerant leak.
- If the low pressure gauge reading will not drop to 101 kPa (30 in-Hg) when the valves on the gauge and manifold set are open and the vacuum pump is operating, close the gauge set valves and observe the low pressure gauge. If the pressure rises rapidly to zero, a large leak is indicated. Recheck the test fitting connections and gauge set connections before installing a new evaporator core or condenser core.
- After evacuating for 45 minutes, close the gauge set valves and stop the vacuum pump. Observe the low pressure gauge; it should remain at the 101 kPa (30 in-Hg) mark. If the low pressure gauge reading rises 34 or more kPa (10 or more in-Hg) of vacuum from the 101 kPa (30 in-Hg) position in 10 minutes, a leak is indicated. If a very small leak is suspected, wait 30 minutes and observe the vacuum gauge. If a small amount of vacuum is lost, operate the vacuum pump with gauge valves open for an additional 30 minutes to remove any remaining refrigerant from the oil in the evaporator core or condenser core. Then recheck for loss of vacuum. If a very small leak is suspected, allow the system to sit overnight with vacuum applied and check for vacuum loss.
- If the evaporator core or condenser core does leak, as verified by the above procedure, install a new evaporator core or condenser core.
A/C Compressor - External Leak Test
- Install the A/C Pressure Test Adapter on the port of the A/C compressor, using the existing manifold retaining bolt.
- Connect the high and low pressure lines of a manifold gauge set or a refrigerant recovery/recycling station such as the R-134a A/C service center to the corresponding fittings on the A/C Pressure Test Adapter.
- Attach the center hose of a manifold gauge set to a refrigerant container standing in an upright position.
- Hand-rotate the compressor shaft 10 complete revolutions to distribute the oil inside the A/C compressor.
- Open the low pressure gauge valve, the high pressure gauge valve and the valve on the refrigerant container to allow the refrigerant vapor to flow into the A/C compressor.
- Using the Refrigerant Leak Detector, check for leaks at the compressor shaft.
- If a shaft or external leak is found, install a new A/C compressor.
- When the leak test is complete, recover the refrigerant from the compressor.
Diagnostic Table
Pinpoint Test O
O1
Additional Possible Cause Components Associated With Inadequate Compressor Operation
- DIAGNOSTIC CHART High (Discharge) Pressure Low (Suction) Pressure Component - Causes High or clutch cycling High Condenser - inadequate airflow. High Normal to high Engine - overheating. Normal to high Normal Refrigerant overcharge - air in refrigerant. Normal to low High Thermostatic expansion valve Normal to low Normal to high A/C suction line - partially restricted or plugged (1) . Normal to low Low or clutch cycling Low refrigerant charge, A/C suction line - partially restricted or plugged. Erratic operation or compressor not running Evaporator discharge temperature sensor - poor connection at A/C clutch connector. A/C electrical circuit erratic - see A/C Electrical Circuit Wiring Diagram. Normal to low High Compressor - low performance. Additional Possible Cause Components Associated With Inadequate Compressor Operation Compressor drive belt - loose Compressor clutch - slipping Clutch coil open - shorted, or loose mounting Control assembly Clutch wiring circuit - high resistance, open or blown fuse Compressor operation interrupted by PCM Additional Possible Cause Components Associated With a Damaged Compressor Incorrect clutch air-gap Receiver/drier - plugged Refrigerant leaks (1) Low pressure reading will be normal to high if pressure is taken at accumulator and if restriction is downstream of service access valve.
Scheme 27
- Check the A/C clutch air gap at three equally spaced places between the clutch hub and the A/C clutch pulley.
- Remove the A/C clutch. Add or remove spacers between the A/C clutch and the compressor shaft until clearance is within specifications.
Scheme 28
Scheme 29
Scheme 30
Scheme 31
Scheme 32
Scheme 33
Scheme 34
- Turn both valves on the R-134a Manifold Gauge Set clockwise to close the low- and high-pressure hoses to the center manifold and center hose.
- Remove the A/C charging valve cap from the high-pressure service gauge port valve.
- Connect the R-134a Manifold Gauge Set high-pressure hose and the R-134a high side quick disconnect to the high-pressure service gauge port valve.
- Raise the vehicle. For additional information, refer to «LIFTING»(ref-207545-S28498965772005113000000) .
- Remove the screws and the left sight shield.
- Remove the A/C charging valve cap (19D702) from the low-pressure service gauge port valve.
- Connect the R-134a Manifold Gauge Set low-pressure hose and the R-134a low side quick disconnect to the low-pressure service gauge port valve.
- To disconnect the manifold and gauge set, reverse the connection procedure.
