Diagnostic Aids

Perform this test when instructed during QUICK TEST or if directed by other test procedures. This system test is intended to diagnose and isolate intermittent problems for the following:

All Engine Control Sub-Systems
Vehicles With Coil Pack Ignition Systems

The intermittent test table is used to determine which test to perform for the suspect circuit. See INTERMITTENT TEST table. Corresponding Parameter Identification (PIDs) for each circuit are listed. Some circuits do not have an associated PID and can be measured with a Digital Volt-Ohmmeter (DVOM). If vehicle has coil pack ignition system and engine is a no-start, perform ignition test. Go to step 50).

INTERMITTENT TEST

PID

Associated Circuit

Test Type

4X4L

Input

ACCS

A/CCS

Input

ACP & ACP V

A/CP

Input

⁽¹⁾

AFC

Input

AIR

Output

AIR B

AIRB

Output

AIR D

AIRD

Output

AIR M

AIRM

Input

BPP/BOO

BPP

Input

⁽¹⁾

BPS

Input

CAS GND

CASE GND

Input

CCS

Output

⁽¹⁾

CD-A (Primary)

Output

⁽¹⁾

CD-B (Primary)

Output

⁽¹⁾

CD-C (Primary)

Output

⁽¹⁾

CD-D (Primary)

Output

⁽¹⁾

CD-E (Primary)

Output

⁽¹⁾

CD-F (Primary)

Output

⁽¹⁾

CD-G (Primary)

Output

⁽¹⁾

CD-H (Primary)

Output

⁽¹⁾

CD-I (Primary)

Output

⁽¹⁾

CD-J (Primary)

Output

CFIL

Output

CHT & CHT V

CHT

Input

CHTIL

Output

⁽¹⁾

CKP(+)

Input

⁽¹⁾

CMP

Input

CPP/PNP

CPP

Input

⁽¹⁾

CTO

Output

⁽¹⁾

DOL

Output

DPFEGR

Input

ECT & ECT V

ECT

Input

⁽¹⁾

EGRMC 1

Output

⁽¹⁾

EGRMC 2

Output

⁽¹⁾

EGRMC 3

Output

⁽¹⁾

EGRMC 4

Output

EFTA & EFTA V

EFT-A

Input

EFTB & EFTB V

EFT-B

Input

EGRVR

Output

EPC & EPC V

EPC

Output

⁽¹⁾

EPC 2

Output

⁽¹⁾

EPC 3

Output

EVAPCP & EVAPDC

EVAPCP

Output

EVAPCV

Output

EVAPPF

Input

LFC

Output

Input

FLI & FLI V

FLI

Input

Output

FPM & FP M

FPM

Input

FRP & FRP V

FRP

Input

FSV

Output

FSVM

Input

FTP & FTP V

FTP

Input

GENFDC

Output

GFS

Input

⁽¹⁾

HCDS

Input

HFC

Output

O2S11

HO2S-11

Input

O2S12

HO2S-12

Input

O2S21

HO2S-21

Input

O2S22

HO2S-22

Input

HTR11

HTR-11

Output

HTR12

HTR-12

Output

HTR21

HTR-21

Output

HTR22

HTR-22

Output

IAC

Output

IAT & IAT V

IAT

Input

IAT2

Input

IAT2 V

Ouput

⁽¹⁾

ILC

Input

IMRC

Output

IMRCM

Input

⁽¹⁾

IMSC

Output

IMTV

IMT Valve

Output

FUELPW1

INJ-1

Output

FUELPW1

INJ-2

Output

FUELPW1

INJ-3

Output

FUELPW1 Or FUELPW2

INJ-4

Output

FUELPW1 Or FUELPW2

INJ-5

Output

FUELPW2

INJ-6

Output

FUELPW2

INJ-7

Output

FUELPW2

INJ-8

Output

FUELPW2

INJ-9

Output

FUELPW2

INJ-10

Output

KS1 & KS2

Input

LFC

Output

⁽¹⁾

LFP

Output

MAF & MAF V

MAF

Input

MFC

Output

MIL

Output

OCTADJ

OCT ADJ

Input

OSS

Input

⁽¹⁾

PATSIL

Output

⁽¹⁾

PATSIN

Input

⁽¹⁾

PATSOUT

Output

⁽¹⁾

PATSTRT

Output

CPP/PNP

PNP

Input

PSP & PSP V

PSP

Input

PTO

Input

⁽¹⁾

SCC

Output

⁽¹⁾

SCMA

Output

⁽¹⁾

SCMB

Output

⁽¹⁾

SCMC

Output

⁽¹⁾

SCVM

Input

⁽¹⁾

SIL

Output

SCB

Output

SCICP

Output

SS1

Output

SS2

Output

SS3

Output

TCC

Output

TCIL

Output

TCS

Input

TFT & TFT V

TFT

Input

⁽¹⁾

THTRC

Output

TMAP

Input

TP & TP V

Input

TPB & TPB V

TPB

Input

⁽¹⁾

TPO

Output

TR & TR V

Input

TSS/ISS

TSS

Input

CAMDCR & RCAM

VCT

Output

VPWR

Input

⁽¹⁾

VREF

Output

⁽¹⁾

VSO

Output

VSS

VSS+

Input

WAC

Output

⁽¹⁾	PID is not available for this circuit. Use DVOM.

1) Direction For Intermittent Diagnostic Path

There are 2 main procedures used in this system test to isolate and repair an intermittent problem. One procedure uses the Rotunda Distributorless Ignition System Tester (DIST) (007-00075) and the other uses a scan tool and a Digital Volt-Ohmmeter (DVOM). The DIST is used on vehicles with coil pack ignition systems. If vehicle has an ignition problem and is equipped with coil pack ignition, go to step 50). If vehicle does not have an ignition problem or DIST is not available, go to next step.

2) Perform PCM Reset To Clear FMEM

Eliminating FMEM will ensure reproduction of any PCM related symptom. If PCM reset produce has already been performed, go to next step. Ensure freeze frame data has been recorded before resetting PCM. If PCM reset procedure has not been performed, perform PCM RESET PROCEDURE under CLEARING CODES under SELF-DIAGNOSTIC SYSTEM. After performing PCM reset procedure, go to next step.

3) Select PIDs Related To Symptom

Scan tool and a list of PIDs must be used to indicate area of fault. Obtain symptom from customer description. Use REFERENCE VALUE SYMPTOM table and REFERENCE VALUE/PID MEASUREMENT SIGNAL table in appropriate PIN VOLTAGE/PID VALUE CHARTS article to identity PIDs that relate to symptom. Note and make a list of symptom related PIDs and go to next step.

4) Symptom Verification

Path to symptom verification is optional, but is recommended for the following reasons:
- If Vehicle Is In For A Repeat Repair
- No DTCs Present
- Customer Has Difficulty Describing Symptom
If symptom needs to be verified, go to next step. If symptom is known and does not need to be verified, go to step 11).

NOTE: Only DTCs that illuminate Malfunction Indicator Light (MIL) will trigger freeze frame data.

5) Collect All Available Freeze Frame Data To Aid In Symptom Verification
Collect as much freeze frame data as possible to aid in determining intermittent fault area. Note any freeze frame data that was recorded in step 2) or during QUICK TEST . Note any Continuous Memory DTCs that were present prior to performing PCM RESET in step 2). Obtain any information from customer that would aid in determining fault area. Go to next step.

NOTE: A road test may be necessary to recreate conditions that originally caused DTC to set.

6) Attempt To Recreate Symptom
Using scan tool, select PIDs displayed in freeze frame data (if available) and PIDs on list which were noted in step 3). Using freeze frame data recorded earlier, recreate conditions described by each freeze frame PID. Pay particular attention to ECT, LOAD, RPM and VSS PIDs. Use any information available from customer to aid in producing conditions for recreating symptom. When symptom occurs, press trigger on scan tool to begin recording. Refer to scan tool manufacturer's instruction manual for recorder function operation. If symptom is reproduced, go to step 11). If symptom cannot be reproduced, go to next step.

NOTE: PIDs for PCM outputs in PIN VOLTAGE/PID VALUE TABLES in appropriate PIN VOLTAGE/PID VALUE CHARTS article represent commanded values only. Circuit measurements made with DVOM indicate actual output status. If circuit measurement made with a DVOM differs from scan tool PID value, a circuit fault may be indicated. PCM input PIDs that differ from circuit measurements made with a DVOM indicate a possible PCM fault.

7) Recreate Symptom Using Intermittent Road Test Procedure
Intermittent road test procedure is the last attempt to locate area of problem before physically disturbing vehicle circuits. Intermittent road test procedure requires monitoring PID values or making circuit measurements with a DVOM under 4 conditions: Key On Engine Off (KOEO), HOT IDLE, and/or vehicle road test at 30 MPH, and/or 55 MPH. During road test at 30 MPH and/or 55 MPH, a ride along assistant is necessary. Use PID values and circuit values in PIN VOLTAGE/PID VALUE TABLES in appropriate PIN VOLTAGE/PID VALUE CHARTS article to compare with actual PID values and circuit measurements made during road test. Perform KOEO condition listed in PIN VOLTAGE/PID VALUE TABLES in appropriate PIN VOLTAGE/PID VALUE CHARTS article. Turn ignition switch to ON position. Using scan tool, select and monitor values. Using a DVOM, measure circuits at PCM terminal identified in PIN VOLTAGE/PID VALUE TABLES in appropriate PIN VOLTAGE/PID VALUE CHARTS article. Compare scan tool PID values with circuit values made with DVOM. If any PID values are out of range, go to step 11). If all PID values are within range, go to next step.

8) Recreate Symptom Using HOT IDLE Road Test Procedure

Start engine and allow to idle. Ensure engine is at normal operating temperature of at least 195°F (87°C). Continue to monitor same PIDs and circuits as in step 7) at HOT IDLE. If any PID values are out of range, go to step 11). If all PID values are within range, go to next step.

9) Recreate Symptom Using 30 MPH Road Test Procedure

Road test vehicle at 30 MPH and continue to monitor same PIDs and circuits as in step 7). If any PID values are out of range, go to step 11). If all PID values are within range, go to next step.

10) Recreate Symptom Using 55 MPH Road Test Procedure

Road test vehicle at 55 MPH and continue to monitor same PIDs and circuits as in step 7). If any PID values are out of range, go to next step. If all PID values are within range, it is now necessary to physically disturb selected vehicle circuits in an attempt to recreate intermittent problem. Go to next step.

11) Select Circuits To Be Tested From Intermittent Test Table

Remain in scan tool PID selection menu. If symptoms were verified while performing steps 7)- 10) (intermittent road tests), select PIDs or circuits that values did not match PID values or circuit values in PIN VOLTAGE/PID VALUE TABLES in appropriate PIN VOLTAGE/PID VALUE CHARTS article. If symptoms were not verified performing steps 7)- 10), select PIDs noted in list made in step 3). Match selected PIDs (from steps 7)- 10) or from list made in step 3) to corresponding circuit in INTERMITTENT TEST table. It is possible to have more than one circuit to test. If a PID recording was made with scan tool in step 6), it may be helpful to replay recording at this time. Using INTERMITTENT TEST table, determine test to perform (input or output). To perform input test, go to next step. To perform output test, go to step 16). If PID or circuit is not listed in INTERMITTENT TEST table, go to SYMPTOMS in TROUBLE SHOOTING - NO CODES article and diagnose driveability symptom.

12) KOEO Intermittent Input Test Procedure For PCM Sensors

Using circuits selected from INTERMITTENT TEST table, select only recommended PIDs to monitor with scan tool. If a PID is not available for a circuit, use a DVOM to monitor circuit. Go to area of suspect wiring or component fault. Turn ignition switch to ON position. If input is a switch-type component, turn switch on manually. Observe PID or DVOM value while lightly tapping on component, and then wiggling sensor wiring harness from component to PCM. If a fault is indicated, PID value or DVOM reading will suddenly change. Compare to correct KOEO values listed in PIN VOLTAGE/PID VALUE TABLES in appropriate PIN VOLTAGE/PID VALUE CHARTS article. If no fault is indicated, go to next step. If a fault is indicated, isolate fault and repair as necessary. If wiring harness and connector(s) is okay, replace suspect component.

CAUTION: Ensure hands, clothing or tools are clear of cooling fans, engine drive belts and/or hot surfaces while performing test steps with engine running.

13) KOER Intermittent Input Test Procedure For PCM Sensors
Start engine and allow to idle. Continue to monitor PIDs and/or circuits as in step 12). Go to area of suspect wiring or component fault. If input is a switch-type component, turn switch on manually. Observe PID or DVOM value while lightly tapping on component, and then wiggling sensor wiring harness from component to PCM. If a fault is indicated, value will suddenly change. Compare to correct HOT IDLE values listed in appropriate PIN VOLTAGE/PID VALUE CHARTS article. If no fault is indicated, turn ignition switch to OFF position and go to next step. If a fault is indicated, isolate fault and repair as necessary. If wiring harness and connector(s) is okay, replace suspect component.

14) KOEO Intermittent Water Soak Test Procedure For PCM Sensors

Turn ignition switch to ON position. Continue to monitor PIDs and/or circuits as in step 13). Go to area of suspect wiring or component fault. If input is a switch-type component, turn switch on manually. While observing PID or DVOM value, lightly spray water on suspect component, circuit or connectors from component to PCM. Include any relays or relay modules associated with fault. If a fault is indicated, value will suddenly change. Compare to correct KOEO values in appropriate PIN VOLTAGE/PID VALUE CHARTS article. If no fault is indicated, go to next step. If a fault is indicated, isolate fault and repair as necessary. If wiring harness and connector(s) is okay, replace suspect component.

15) KOER Intermittent Water Soak Test Procedure For PCM Sensor

Start engine and allow to idle. Continue to monitor PIDs and/or circuits as in step 14). Go to area of suspect wiring or component fault. If input is a switch-type component, turn switch on manually. While observing PID value, lightly spray water on suspect component, circuit or connectors from component to PCM. Include any relays or relay modules associated with fault. If a fault is indicated value will suddenly change. Compare to correct HOT IDLE values in appropriate PIN VOLTAGE/PID VALUE CHARTS article. If no fault is indicated, go to next step. If a fault is indicated, isolate fault and repair as necessary. If wiring harness and connector(s) is okay, replace suspect component.

NOTE: PIDs selected from INTERMITTENT TEST table will display commanded values only. Circuit measurements made with DVOM will indicate actual values.

NOTE: OUTPUT TEST MODE may not control some outputs, such as fuel injectors or ignition coils. To test outputs not controlled by OUTPUT TEST MODE, go to step 17). Ensure hands, clothing or tools are clear of cooling fans, as they may turn on when OUTPUTS are commanded ON.

NOTE: OUTPUT TEST MODE defaults to its normal state after 10 minutes.

16) KOEO Intermittent Output Test Procedure For PCM Actuators
Using circuits chosen from INTERMITTENT TEST table, select only recommended PIDs to monitor with scan tool. Also use a DVOM to compare circuit values with scan tool PID values. If a PID is not available for a circuit, use a DVOM to monitor circuit. Turn ignition switch to ON position. Using scan tool, access OUTPUT TEST MODE. See OUTPUT TEST MODE under ADDITIONAL SYSTEM FUNCTIONS.
Using scan tool, turn ALL OUTPUTS ON. Go to area of suspect wiring or component fault. Observe PID value while lightly tapping on component, and then wiggling sensor wiring harness from component to PCM. If a fault is indicated, value will suddenly change. Also, compare actual values with KOEO values in appropriate PIN VOLTAGE/PID VALUE CHARTS article. If no fault is indicated, go to next step. If a fault is indicated, isolate fault and repair as necessary. If wiring harness and connector(s) is okay, replace suspect component.

17) KOER Intermittent Output Test Procedure For PCM Actuators

Start engine and allow to idle. Continue to monitor PIDs and/or circuits as in step 16). Go to area of suspect wiring or component fault. Compare DVOM measurement to PID values while lightly tapping on component.
NOTE: If a coil for a coil on plug application has been tapped and is suspect, turn ignition switch to OFF position. Remove coil. Using DVOM, check continuity between spark plug terminal and signal terminal of coil. Observe DVOM while lightly tapping on coil. A large fluctuation in resistance indicates an intermittent open in coil. Replace coil as necessary. If coil is okay, check wiring harness.

Observe PID value while wiggling actuator wiring harness from component to PCM. A fault is indicated by a change in idle, or a sudden change or mismatch in PID value. Also, compare actual values with HOT IDLE values in appropriate PIN VOLTAGE/PID VALUE CHARTS article. If no fault is indicated, go to next step. If a fault is indicated, isolate fault and repair as necessary. If wiring harness and connector(s) is okay, replace suspect component.

WARNING: Avoid contact with PCM, Generic Electronic Module (GEM) or other modules when performing water soak test on electrical components and/or harnesses.

NOTE: OUTPUT TEST MODE may not control some outputs, such as fuel injectors. To test outputs not controlled by OUTPUT TEST MODE, go to step 19).

18) KOEO Output Intermittent Water Soak Test Procedure For PCM Actuators
Turn ignition switch to ON position. Using scan tool, access OUTPUT TEST MODE. See OUTPUT TEST MODE under ADDITIONAL SYSTEM FUNCTIONS. Turn all outputs on. Continue to monitor PIDs and/or circuits as in step 17). Go to area of suspect wiring or component fault. While observing PID or DVOM value, lightly spray water on suspect component, circuit or connectors from component to PCM. Include any relays or relay modules associated with fault. A fault is indicated by a change a sudden change or mismatch in PID value. Also, compare actual values with KOEO values in appropriate PIN VOLTAGE/PID VALUE CHARTS article. If no fault is indicated, go to next step. If a fault is indicated, isolate fault and repair as necessary. If wiring harness and connector(s) is okay, replace suspect component.

WARNING: Avoid contact with PCM, Generic Electronic Module (GEM) or other modules when performing water soak test on electrical components and/or harnesses.

19) KOER Output Intermittent Water Soak Test Procedure For PCM Actuators
Start engine and allow to idle. Continue to monitor PIDs and/or circuits as in step 18). Go to area of suspect wiring or component fault. While observing PID value, lightly spray water on suspect component, circuit or connectors from component to PCM. A fault is indicated by a change in idle, or a sudden change or mismatch in PID value. Also, compare actual values with HOT IDLE values in appropriate PIN VOLTAGE/PID VALUE CHARTS article. If no fault is indicated, go to next step. If a fault is indicated, isolate fault and repair as necessary. If wiring harness and connector(s) is okay, replace suspect component.

NOTE: An intermittent mechanical problem can cause a good PCM system to react abnormally.

20) Check For Intermittent Mechanical Problems
If not done previously, inspect mechanical systems relating to DTC or symptom. Check the following:
- Check if engine rocks during acceleration. If excessive movement is detected, check motor mounts.
- Check for excessive component movement while driving vehicle during conditions that would cause vibrations (high RPM, rough roads, etc.).
- Check accelerator and transmission linkages for contact or interference.
If any problems are detected, repair as necessary. If no problems are detected, fault cannot be identified at this time. Check for related Technical Service Bulletins (TSBs) for additional help. Testing is complete.

NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 20) to step 50). No test procedures have been omitted.

NOTE: The following step is for vehicle equipped with coil pack ignition system. Testing must be performed using Rotunda Distributorless Ignition System Tester (DIST) (007-00075). If DIST is not available, go to step 2) and continue testing.

50) Intermittent Ignition Test Procedure
Check sensor shield connector. Ensure all accessories are off and battery is fully charged. Perform QUICK TEST . If any DTCs are present, service DTCs as necessary before continuing with this test. If no DTCs are present, connect Rotunda Distributorless Ignition System Tester (DIST) (007-00075) and go to next step.

51) Install Distributorless Ignition System Tester

Turn ignition switch to OFF position. Ensure all accessories are off. Install correct overlay and appropriate program cartridge into DIST. Connect proper harness adapter to DIST 104-Pin PCM Adapter (007-00110). Set rotary knob to position "1". Ensure WIGGLE TEST switch is off. On B2500, set System Type switch to DUAL PLUG position. On all other 4-cylinder engines, set System Type switch to NON DUAL PLUG position.
NOTE: WIGGLE TEST can only be used during Key On Engine Off (KOEO) Self-Test. WIGGLE TEST monitors circuits for intermittent faults and has 3 different modes (A, B and C). MODE A checks for shorts to B+ or VPWR, MODE B checks for open circuits, and MODE C checks for shorts to ground. Attempt to duplicate fault conditions by wiggling wiring harness and tapping on connectors and components. DIST will beep and turn on appropriate LED for circuit where fault is detected.

On all models, Disconnect PCM connector(s). Connect tester to PCM harness connector. Turn ignition switch to ON position. Press RESET button on tester. Tester will perform aelf-test and all test LEDs will light and a beep will be heard. If CASE GND (CKP SHIELD) FAULT MEMORY LED (EI only) stays on, connect a jumper wire between PCM case to chassis ground and continue with test. If tester does not perform KOEO self-test or VPWR LED does not turn on, refer to DIST warranty information. If DIST performs KOEO self-test and VPWR LED is on, go to step 223).

NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 51) to step 223). No test procedures have been omitted.

223) Recreate Problem

With DIST connected to vehicle, attempt to duplicate fault by road testing vehicle. If vehicle is a no-start, crank engine for 5-10 seconds. If FAULT MEMORY LEDs are off with engine running or during engine cranking, attempt to recreate fault with FREEZE FRAME DATA or information from customer, then go to step 234). If any FAULT MEMORY LED is on, go to step 234).
NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 223) to step 234). No test procedures have been omitted.

234) Wiggle Test Mode

Set DIST WIGGLE TEST switch to ON position. Set MODE switch to "A" position. Press RESET button. Wait for WIGGLE TEST ACTIVE LED to come on. Lightly tap on components and wiggle and bend wiring harness and connectors. Repeat test with MODE switch in "B" and "C" position. If FAULT MEMORY LEDs are off, replace PCM. If any FAULT MEMORY LED is on, press RESET button and wait for WIGGLE TEST ACTIVE LED to come on. Continue to test until intermittent fault is located. Repair as necessary and retest.