Diagnostic Procedure
WARNING: This page is about a different car, the 2005 Jeep Liberty. However, it is still accessible from the selected car via links, so may be relevant.
DIAGNOSTIC TEST REFERENCE - P0870-OD HYDRAULIC PRESSURE TEST FAILURE
| 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 the engine DTC's. Check and repair all engine DTC's prior to performing 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 the flash level of the transmission controller. Some problems are corrected by software upgrades to the transmission controller.
NOTE:
Check for applicable TSB's related to the problem. Perform this procedure prior to Symptom diagnosis.ContinueGo To 2 |
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| 2 | With the DRBIII®, check for other Transmission DTC's. Are there any Line Pressure related DTC's P0867, P0932, P0868, P0869, or P0944 present? Yes --> Refer to appropriate test. Perform 45RFE/545RFE TRANSMISSION VERIFICATION TEST - VER 1 . No --> Go To 3 |
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| 3 | With the DRBIII®, check for other Transmission DTC's. Is the DTC P0733 and/or P0871 present also? Yes --> Replace the Transmission Solenoid/TRS Assembly per the Service Information. Perform 45RFE/545RFE TRANSMISSION VERIFICATION TEST - VER 1 . No --> Go To 4 |
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| 4 | With the DRBIII®, Check the STARTS SINCE SET counter for P0870.
NOTE:
This counter only applies to the last DTC set. Is the STARTS SINCE SET counter 2 or less? Yes --> Go To 5 No --> Go To 18 |
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| 5 | Start engine. Warm transmission to 82°C or 180 °F. Firmly apply brakes. With the DRBIII®, monitor the Transmission Line Pressure. Move the shift lever to each gear position and record the Line Pressure reading. Allow the pressure to stabilize for at least 5 seconds in each range. Did the Line Pressure remain at a steady value between 585 and 655 kPa or 85 and 95 PSI? Yes --> Go To 6 No --> Go To 10 |
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| 6 | Ignition on, engine not running. With the DRBIII®, monitor the Line Pressure while firmly pushing the Line Pressure Sensor connector towards the Transmission. Did the Line Pressure change to about 207 kPa or 30 PSI when the connector was pushed? Yes --> Disconnect and properly reconnect the Line Pressure Sensor harness connector. Inspect terminals and repair as necessary. Perform 45RFE/545RFE TRANSMISSION VERIFICATION TEST - VER 1 . No --> Go To 7 |
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| 7 | Turn the ignition off to the lock position. Remove the Starter Relay.
NOTE:
Failure to remove Starter Relay can cause a TCM - No Response condition. Install the Transmission Simulator, Miller tool #8333. With the Transmission Simulator select the "OFF" position on the "Input/Output Speed" switch. Ignition on, engine not running. With the DRBIII®, monitor the Line Pressure during the following step. Using the Transmission Simulator, turn the selector switch to each of the 3 Line Pressure positions.
NOTE:
All three DRBIII® Line Pressure readings should be steady and +/- 2.0 PSI of the reading specified on the Transmission Simulator. Did the Line Pressure remain steady in all 3 positions? Yes --> Replace the Line Pressure Sensor per the Service Information. Perform 45RFE/545RFE TRANSMISSION VERIFICATION TEST - VER 1 . No --> Go To 8 |
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| 8 | Turn the ignition off to the lock position. Disconnect the TCM harness connector. Disconnect the Line Pressure Sensor harness connector.
NOTE:
Check connectors - Clean/repair as necessary. Measure the resistance of the 5-volt Supply circuit from the Line Pressure Sensor harness connector to the TCM harness connector. Is the resistance above 5.0 ohms? Yes --> Repair the 5-volt supply circuit for an open. Perform 45RFE/545RFE TRANSMISSION VERIFICATION TEST - VER 1 . No --> Go To 9 |
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| 9 | Turn the ignition off to the lock position. Disconnect the TCM harness connector. Disconnect the Line Pressure Sensor harness connector.
NOTE:
Check connectors - Clean/repair as necessary. Measure the resistance between ground and the 5-volt Supply circuit. Is the resistance below 5.0 ohms? Yes --> Repair the 5-volt Supply circuit for a short to ground. Perform 45RFE/545RFE TRANSMISSION VERIFICATION TEST - VER 1 . No --> Go To 17 |
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| 10 | Turn the ignition off to the lock position. Remove the Starter Relay.
NOTE:
Failure to remove the Starter Relay can cause a TCM - No Response condition. Install the Transmission Simulator, Miller tool #8333.
NOTE:
Check connectors - Clean/repair as necessary. Ignition on, engine not running. With the DRBIII®, monitor the OD Pressure Switch state during the following steps. With the Transmission Simulator Miller tool# 8333, place the selector switch on OD. While pressing the Pressure Switch test button, wiggle the wiring harness and connectors pertaining to the OD Pressure Switch. Did the OD pressure switch state change to closed and remain closed while wiggling the wires? Yes --> Go To 11 No --> Go To 13 |
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| 11 | Remove and inspect the Transmission Oil Pan per the Service Information. Does the Transmission Oil Pan contain excessive debris or contamination? Yes --> Repair the cause of the excessive debris in the Transmission Oil Pan. Refer to the Service Information for the proper procedures. Perform 45RFE/545RFE TRANSMISSION VERIFICATION TEST - VER 1 . No --> Go To 12 |
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| 12 | If there are no possible causes remaining, view repair. Repair Repair Internal Transmission as necessary. Disassemble and inspect the Valve Body and repair or replace as necessary. If no problems are found in the Valve Body, replace the Transmission Solenoid/TRS Assembly. Perform 45RFE/545RFE TRANSMISSION VERIFICATION TEST - VER 1 . |
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| 13 | Turn the ignition off to the lock position. Disconnect the TCM harness connector. Disconnect the Transmission Solenoid/TRS Assembly harness connector
NOTE:
Check connectors - Clean/repair as necessary. Measure the resistance of the OD Pressure Switch Sense circuit from the TCM harness connector to the Transmission Solenoid/TRS Assembly harness connector. Is the resistance above 5.0 ohms? Yes --> Repair the OD Pressure Switch Sense circuit for an open. Perform 45RFE/545RFE TRANSMISSION VERIFICATION TEST - VER 1 . No --> Go To 14 |
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| 14 | Turn the ignition off to the lock position. Disconnect the TCM harness connector. Disconnect the Transmission Solenoid/TRS Assembly harness connector.
NOTE:
Check connectors - Clean/repair as necessary. Measure the resistance between ground and the OD Pressure Switch Sense circuit. Is the resistance below 5.0 ohms? Yes --> Repair the OD Pressure Switch Sense circuit for a short to ground. Perform 45RFE/545RFE TRANSMISSION VERIFICATION TEST - VER 1 . No --> Go To 15 |
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| 15 | Turn the ignition off to the lock position. Disconnect the TCM harness connector. Disconnect the Transmission Solenoid/TRS Assembly harness connector. Remove the Transmission Control Relay.
NOTE:
Check connectors - Clean/repair as necessary. Connect a jumper wire between the Fused B+ circuit and the Transmission Control Relay Output circuit in the Transmission Control Relay connector. Ignition on, engine not running. Measure the voltage of the OD Pressure Switch Sense circuit in the TCM harness connector. Is the voltage above 0.5 volt? Yes --> Repair the OD Pressure Switch Sense circuit for a short to voltage. Perform 45RFE/545RFE TRANSMISSION VERIFICATION TEST - VER 1 . No --> Go To 16 |
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| 16 | Turn the ignition off to the lock position. Disconnect the Transmission Solenoid/TRS Assembly harness connector. Remove the Transmission Control Relay. Connect a jumper wire between the Fused B(+) circuit and the Transmission Control Relay Output circuit in the Transmission Control Relay connector. Ignition on, engine not running. Using a 12-volt test light connected to ground, check the Transmission Control Relay Output circuit at the Transmission Solenoid/TRS Assembly harness connector.
NOTE:
The test light must illuminate brightly. Compare the brightness to that of a direct connection to the battery. Does the test light illuminate brightly? Yes --> Go To 17 No --> Repair the Transmission Control Relay Output circuit for an open. If the fuse is open make sure to check for a short to ground. Perform 45RFE/545RFE TRANSMISSION VERIFICATION TEST - VER 1 . |
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| 17 | 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 Transmission Control Module per the Service Information. WITH THE DRBIII® PERFORM QUICK LEARN Perform 45RFE/545RFE TRANSMISSION VERIFICATION TEST - VER 1 . |
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| 18 | The conditions necessary to set this DTC are not present at this time. Using the schematics as a guide, inspect the wiring and connectors specific to this circuit. Wiggle the wires while checking for shorts and open circuits. With the DRBIII®, check the EATX DTC EVENT DATA to help identify the conditions in which the DTC was set. Were there any problems found? Yes --> Repair as necessary. Perform 45RFE/545RFE TRANSMISSION VERIFICATION TEST - VER 1 . No --> Test Complete. |
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