TEST
ACTION
APPLICABILITY
5
With the DRBIII
t, read the FREEZE FRAME DATA.
Use the FREEZE FRAME DATA and attempt to determine the cause of the Misfire
DTC.
In the FREEZE FRAME DATA, is the engine RPM over 3000 and the operating temp
normal?
All
Yes
→ Test CMP and CKP signals with Lab Scope, check valve timing,
and perform running vacuum test.
Perform POWERTRAIN VERIFICATION TEST VER - 5 - 1.6L.
No
→ Go To 6
6
Note: Anything that affects the speed of the crankshaft can cause a misfire
DTC.
The following are other possible causes for mis-fire:
Injector harness connectors, secondary ignition problem, mechanical engine problem,
PCM power grounds, irregular cam and crank signal, plugged injectors, restricted
exhaust, intake restriction, damaged trigger wheel, contaminated fuel, or vacuum
leak.
Weak valve springs, carbon deposits on valves, or accessory drive belt (serpentine
belt).
Check for any TSB’s that may relate to a Misfire DTC.
Do any of the above causes exist?
All
Yes
→ Repair as necessary.
Perform POWERTRAIN VERIFICATION TEST VER - 5 - 1.6L.
No
→ Go To 7
7
NOTE: Before Continuing: Disconnect the PCM harness connector and
check the related wiring terminals for corrosion, damage or terminal push
out. Repair as necessary.
Using the schematics as a guide, inspect the wire harness and connectors. Pay
particular attention to all Power and Ground circuits.
If there are no possible causes remaining, view repair.
All
Repair
Replace and program the Powertrain Control Module in accor-
dance with the Service Information.
Perform POWERTRAIN VERIFICATION TEST VER - 5 - 1.6L.
8
NOTE: The conditions that set the DTC are not present at this time.
An intermittent problem may have been caused by moisture in the secondary
ignition.
WARNING: WHEN THE ENGINE IS OPERATING, DO NOT STAND IN A
DIRECT LINE WITH THE FAN. DO NOT PUT YOUR HANDS NEAR THE
PULLEYS, BELTS, OR FAN. DO NOT WEAR LOOSE CLOTHING.
Using the DRBIII
t, refer to DTC and Freeze Frame information and attempt to
duplicate the conditions that set the Misfire DTC.
Pay particular attention to the DTC setting conditions, such as speed, temp, load,
and map vacuum.
Are any misfires detected when operating under conditions similar to when the DTC
was set?
All
Yes
→ Restart diagnostics beginning with Test 2.
Perform POWERTRAIN VERIFICATION TEST VER - 5 - 1.6L.
No
→ Test Complete.
106
DRIVEABILITY - 1.6L GAS
P0300-MULTIPLE CYLINDER MIS-FIRE —
Continued