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Home >> Jeep >> 2005 >> Wrangler Rubicon, Standard >> Repair and Diagnosis >> External Pages >> Different car >> Section 488 (Powertrain Diagnostic Procedures - Gas) >> Diagnostic Information And Procedures >> Transmission - 42RLE - Diagnostic Tests >> P0720-Output Speed Sensor Error >> Diagnostic Procedure

Diagnostic Procedure

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P0720-OUTPUT SPEED SENSOR ERROR DIAGNOSTIC TEST REFERENCE

TEST ACTION APPLICABILITY
1
NOTE: Low fluid level can be the cause of many transmission problems. If the fluid level is low locate and repair the leak then check and adjust the fluid level per the Service Information.
NOTE: Always perform diagnostics with a fully charged battery to avoid false symptoms.
With the DRBIII®, read Engine DTC's. Check and repair all Engine DTC's prior to performing any transmission symptom diagnostics.With the DRBIII®, read Transmission DTC's. Record all DTC's and 1 Trip Failures.
NOTE: Diagnose 1 Trip Failures as a fully matured DTC.
Using the wiring diagram/schematic as a guide, inspect the wiring and connectors.Repair as necessary.Perform the Shift Lever Position Test. If the test does not pass, refer to Symptom test for P0706 CHECK SHIFTER SIGNAL .For Gear Ratio DTC's, check and record all CVI's.Most DTC's set on start up but some must be set by driving the vehicle such that all diagnostic monitors have run.
NOTE: Verify flash level of Powertrain Control Module. Some problems are corrected by software upgrades to the Transmission and Engine software.
NOTE: Check for applicable TSB's related to the problem.
Perform this procedure prior to Symptom diagnosis.ContinueGo To 2		 All
2 Start the engine in park.
Raise the drive wheels off of the ground.
WARNING: PROPERLY SUPPORT THE VEHICLE.

Firmly apply the brakes and place the transmission selector in drive.
WARNING: BE SURE TO KEEP HANDS AND FEET CLEAR OF ROTATING WHEELS.

Release the brakes and allow the drive wheels to spin freely.
NOTE: The drive wheels must be turning at this point.

With the DRBIII®, read the Output RPM
Is the Output RPM below 100?
Yes --> Go To 3
No --> Go To 11		 All
3 Turn the ignition off to the lock position.
Remove the Starter Relay.
CAUTION: Removal of the Starter Relay is to prevent a Transmission, NO RESPONSE, condition and disable the starter.

Install the Transmission Simulator, Miller tool #8333 and the Electronic Transmission Adapter kit 8333-1A.
Ignition on, engine not running.
With the Transmission Simulator, set the "Input/Output Speed" switch to "ON" and the rotary switch to the "3000/1250" position.
With the DRBIII®, read the Input and Output RPM.
Does the Input RPM read 3000 and the Output RPM read 1250 (within 50 RPM)?
Yes --> Go To 4
No --> Go To 5		 All
4 If there are no possible causes remaining, view repair.
Repair
Replace the Output Speed Sensor per the Service Information.
Perform 42RLE (NGC) TRANSMISSION VERIFICATION TEST - VER 1 .		 All
5 Turn the ignition off to the lock position.
Disconnect the PCM harness connector.
Disconnect the Output Speed Sensor harness connector.
NOTE: Check connectors - Clean/repair as necessary.
CAUTION: DO NOT PROBE THE PCM HARNESS CONNECTORS. PROBING THE PCM HARNESS CONNECTORS WILL DAMAGE THE PCM TERMINALS RESULTING IN POOR TERMINAL TO PIN CONNECTION. INSTALL MILLER SPECIAL TOOL #8815 TO PERFORM DIAGNOSIS.

Measure the resistance of the Output Speed Sensor Signal circuit from appropriate terminal of special tool #8815 to the Output Speed Sensor harness connector.
Is the resistance above 5.0 ohms?
Yes --> Repair the Output Speed Sensor Signal circuit for an open.
Perform 42RLE (NGC) TRANSMISSION VERIFICATION TEST - VER 1 .
No --> Go To 6		 All
6 Turn the ignition off to the lock position.
Disconnect the PCM harness connector.
Disconnect the Output Speed Sensor harness connector.
NOTE: Check connectors - Clean/repair as necessary.
CAUTION: DO NOT PROBE THE PCM HARNESS CONNECTORS. PROBING THE PCM HARNESS CONNECTORS WILL DAMAGE THE PCM TERMINALS RESULTING IN POOR TERMINAL TO PIN CONNECTION. INSTALL MILLER SPECIAL TOOL #8815 TO PERFORM DIAGNOSIS.

Measure the resistance of the Speed Sensor Ground circuit from the appropriate terminal of special tool #8815 to the Output Speed Sensor harness connector.
Is the resistance above 5.0 ohms?
Yes --> Repair the Speed Sensor Ground circuit for an open.
Perform 42RLE (NGC) TRANSMISSION VERIFICATION TEST - VER 1 .
No --> Go To 7		 All
7 Turn the ignition off to the lock position.
Disconnect the PCM harness connector.
Disconnect the Output Speed Sensor harness connector.
NOTE: Check connectors - Clean/repair as necessary.
CAUTION: DO NOT PROBE THE PCM HARNESS CONNECTORS. PROBING THE PCM HARNESS CONNECTORS WILL DAMAGE THE PCM TERMINALS RESULTING IN POOR TERMINAL TO PIN CONNECTION. INSTALL MILLER SPECIAL TOOL #8815 TO PERFORM DIAGNOSIS.

Measure the resistance between ground and the Output Speed Sensor Signal circuit.
Is the resistance below 5.0 ohms?
Yes --> Repair the Output Speed Sensor Signal circuit for a short to ground.
Perform 42RLE (NGC) TRANSMISSION VERIFICATION TEST - VER 1 .
No --> Go To 8		 All
8 Turn the ignition off to the lock position.
Disconnect the PCM harness connector.
Disconnect the Output Speed Sensor harness connector.
Remove the Transmission Control Relay.
NOTE: Check connectors - Clean/repair as necessary.

Connect a jumper wire between the Fused B+ circuit and Transmission Control Relay Output circuit in the Transmission Control Relay connector.
Ignition on, engine not running.
CAUTION: DO NOT PROBE THE PCM HARNESS CONNECTORS. PROBING THE PCM HARNESS CONNECTORS WILL DAMAGE THE PCM TERMINALS RESULTING IN POOR TERMINAL TO PIN CONNECTION. INSTALL MILLER SPECIAL TOOL #8815 TO PERFORM DIAGNOSIS.

Measure the voltage of the Output Speed Sensor Signal circuit.
Is the voltage above 0.5 volt?
Yes --> Repair the Output Speed Sensor Signal circuit for a short to voltage.
Perform 42RLE (NGC) TRANSMISSION VERIFICATION TEST - VER 1 .
No --> Go To 9		 All
9 Turn the ignition off to the lock position.
Disconnect the PCM harness connector.
Disconnect the TRS harness connector.
Remove the Transmission Control Relay.
NOTE: Check connectors - Clean/repair as necessary.

Connect a jumper wire between the Fused B+ and Transmission Control Relay Output circuits in the Transmission Control Relay connector.
Ignition on, engine not running.
CAUTION: DO NOT PROBE THE PCM HARNESS CONNECTORS. PROBING THE PCM HARNESS CONNECTORS WILL DAMAGE THE PCM TERMINALS RESULTING IN POOR TERMINAL TO PIN CONNECTION. INSTALL MILLER SPECIAL TOOL #8815 TO PERFORM DIAGNOSIS.

Measure the voltage of the Speed Sensor Ground circuit.
Is the voltage above 0.5 volts?
Yes --> Repair the Speed Sensor Ground circuit for a short to voltage.
Perform 42RLE (NGC) TRANSMISSION VERIFICATION TEST - VER 1 .
No --> Go To 10		 All
10 Using the schematics as a guide, inspect the wiring and connectors. Repair as necessary. Pay particular attention to all power and ground circuits.
If there are no possible causes remaining, view repair.
Repair
Replace the Powertrain Control Module per the Service Information. WITH THE DRBIII® PERFORM QUICK LEARN .
Perform 42RLE (NGC) TRANSMISSION VERIFICATION TEST - VER 1 .		 All
11 The conditions necessary to set the DTC are not present at this time.
Using the schematics as a guide, inspect the wiring and connectors specific to this circuit.
Wiggle the wiring and connectors while checking for shorted and open circuits.
With the DRBIII®, check the EATX EVENT DATA to help identify the conditions in which the DTC was set.
Were there any problems found?
Yes --> Repair as necessary.
Perform 42RLE (NGC) TRANSMISSION VERIFICATION TEST - VER 1 .
No --> Test Complete.		 All
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