Without Scan Tool

Diagnostic Flow Diagram:

PZM Status Lights:

SYSTEM
This section explains the mechanics of operating the self-diagnostic system. It may be helpful to refer to Figure 1 while reviewing this material.

HOW TO ENTER DIAGNOSTICS
To enter diagnostics, proceed as follows:

1. Turn the ignition switch "ON".

2. Push the "OFF" and "WARM" buttons on the CCC (Digital Instrument Panel Cluster (IPC)) or the "OFF" and "PASSENGER WARMER" buttons on the Climate Control Panel (CCP) (Analog IPC) simultaneously and hold until the segment check appears on the IPC.

NOTICE: Operating the vehicle in diagnostics for extended time periods without the engine running or without a battery charger will cause the battery to run down and possibly relate false diagnostic information, or cause a "no start" condition. To ensure proper operation, attach a battery charger, if vehicle is to be operated in diagnostics without engine running for an extended time period.

SEGMENT CHECK

The purpose of illuminating the IPC is to verify all segments of the LED displays are working. The turn signal indicators do not light during this check. Further diagnosis should not be attempted unless all segments appear, as this could lead to misdiagnosis. If any portions or segments of the IPC displays are inoperative, the IPC must be replaced.

DIAGNOSTIC TROUBLE CODE (DTC) DISPLAY
After diagnostics is entered, any DTCs stored in computer memory will be displayed. Each DTC consists of the system abbreviation (P - PCM, IP - IPC, AC - Air Control Module (ACM), SD - Supplemental Inflatable Restraint (SIR), TC - TCS, RS - Road Sensing Suspension (RSS), PZ - PZM, IR - Integrated Radio Control Module (IRC), RF - RFA, CC - CCP or PH - PHN), a four digit identifier, and the letter C or H. All DTCs for each system are displayed together, in consecutive order by their four digit number (lowest first - i.e. PZ 2016, PZ 2096, etc.). The final digit of the code, a "C" or an "H", is used to indicate whether the DTC is current or history. A "C" means the malfunction was still present the last time the diagnostic test was run, while "H" means the failure was not present the last time the DTC was tested for. If no DTCs are present for a system, a "NO X CODES" message (with X being the system i.e. PCM, IPC, ACM, SIR, TCS, RSS, PZM, IRC, RFA, CCP or PHN) will be displayed. If the communication line to a component is not operating, a "NO X DATA" message will be displayed, indicating that the IPC could not communicate with that system. At any time during the display of DTCs, if the "MODE" button on the IPC is depressed the system will exit "Service Mode" and go back to normal vehicle operation.

STATUS LIGHTS
While in Service Diagnostics, the displays on the CCC (Digital IPC) or CCP (Analog IPC) may be used to indicate the status of various inputs and operating conditions. The meaning of each word or symbol on the panel will change depending on whether the ACM or PCM system level is selected. This is detailed in the sections covering these systems.

SELECTING THE SYSTEM
After DTCs have been displayed, a specific vehicle system (PCM, IPC, ACM, SIR, TCS, RSS, PZM, IRC, RFA, CCP or PHN) may be selected for testing. The first available system will be automatically displayed (i.e. PCM?). While selecting the system to test, any of the following actions may be taken:

1. Depressing the "HI" button will select the displayed system for testing.

2. Depressing the "LO" button will display the next available system selection. This allows the display to be stepped through all system choices. This list of systems can be repeated following the end of the system list.

3. Depressing the "OFF" button will stop the system selection process and return the display to the beginning of the trouble code sequence.

4. Depressing the "OFF" button twice will return the system to the SEGMENT CHECK.

SELECTING THE TEST TYPE

Having selected a system, the first available test type will be displayed (i.e. PCM DATA?). While selecting a specific test type, any of the following actions may be taken:

1. Depressing the "HI" button will select the displayed test type. At this point the first of several specific tests will appear.

2. Depressing the "LO" button will display the next available test type for the selected system. This allows the display to be stepped through all available test type choices. This list of test types can be repeated following the display of the last test type.

3. Depressing the "OFF" button will stop the test type selection process and return the display to the next available system selection.

DATA, IN PUTS, OUTPUTS, OR OVERRIDES

Selecting the Test

Selection of the "DATA?", "INPUTS?", "OUTPUTS?" or "OVERRIDE?" test types will result in the first available test being displayed. Alphanumeric characters on the display will contain a test code to identify the selection. The alpha characters identify the system and test type (e.g. IPD for IPC DATA) and the digits numerically identify the test (e.g. IPD14 for Ignition Cycle Counter). While selecting a specific test, any of the following actions may be taken:

1. Depressing the "HI" button will display the next higher test number for the selected test type. If this button is pressed with the highest test number displayed, the lowest test number will then appear.

2. Depressing the "LO" button will display the next lower test number for the selected test type. If this button is pressed with the lowest test number displayed, the highest test number will then appear.

3. Depressing the "OFF" button will stop the test selection process and return the display to the next available test type for the selected system.

Parameter Values

DATA

When one of the various data tests is selected, the actual analog value as seen/used by the system is displayed.

INPUTS

Input tests will display the state of the selected device as HI or LO. The display also indicates if the input has changed state so that the technician can activate or deactivate any listed device and return to the display to see if it changed state. If a change of state occurred, an "X" will appear next to the HI/LO indicator, otherwise an "0" will remain displayed. The "X" will only appear once per selected input although the HI/LO indication will continue to change as the input changes. Some tests are momentary and the "X" can be used as an indication of a change.

OUTPUTS

Output cycling can be used to determine if the output tests can be actuated regardless of the inputs and normal program instructions. Once a test in outputs has been selected, the test will display HI and LO for three seconds in each state to indicate the command and output terminal voltage.

OVERRIDES

The displayed function's current operation will be represented as a percentage of its full range, displayed on the DIC. The display will alternate between "-" for 1 second followed by the normal program value for S seconds whenever the value is under normal control (i.e. not being commanded to an override value. While an override is selected, the value may be increased by pressing the "WARM" button or decreased by pressing the "COOL" button. Depending on the item being overridden, the value may remain in the override state or return to normal operation when the "WARM/COOL" button is released. If the display remains at the override value, normal program control can be resumed in one of three ways:

1. Selection of another override test will cancel the current override.

2. Selection of another system will cancel the current override.

3. Overriding the value beyond either extreme (0 or 99) will display "-" momentarily and then jump to the opposite extreme. If the button is released while "-" is displayed, normal program control will resume and the display will again alternate.

IMPORTANT:

When an override test is being commanded, it is possible to observe its effect on any DATA or INPUT test for the selected system. After selecting an override test, pressing the "OFF" button will allow selection of another test type. The CCC (Digital Cluster) or CCP (Analog Cluster) however, will continue to display the selected override. By selecting the desired DATA or INPUT test and pressing the "WARM" or "COOL" button, it is possible to monitor the effect of the override on the displayed DATA/INPUT.

CLEAR CODES

Selection of the "CLEAR CODES?" test will result in the message "CODES CLEAR" being displayed along with the selected system name. This message will appear for 3 seconds and then return to the next available test type.

HOW TO EXIT DIAGNOSTICS

To exit self-diagnostics, depress the "MODE" or "DEFOG" button, or turn the ignition switch off. DTCs are not erased when this is done.

CLIMATE CONTROL IN DIAGNOSTICS

Upon entering diagnostics, the climate control will operate in whatever m(:de was being commanded just prior to depressing the "OFF" and "WARMER" or "PASSENGER WARMER" buttons (unless ACM overrides are used to force the system to new operating parameters). Even though the display may change just as the buttons are touched, the prior operating mode is remembered and will resume after diagnostics is entered. Extended Compressor at Idle (ECI) is not allowed while in the diagnostic mode. This allows observation of system parameters during normal compressor cycles.