P0725-ENGINE SPEED SENSOR CIRCUIT
For a complete wiring diagramRefer to Section 8W.
When Monitored:
Continuously every 7 msec with the ignition on and engine running.
Set Condition:
This DTC will set when the calculated engine speed is less than 390 RPM with the engine running, or greater
than 8000 RPM, for the period of 2.0 seconds. The PCM will place the Transmission in Limp-in when this DTC
is set.Note: This is not a Transmission Input Speed Sensor DTC.
Possible Causes
RELATED ENGINE DTC’S PRESENT
CRANK POSITION SENSOR OR WIRING
POWERTRAIN CONTROL MODULE
Always perform the 45RFE/545RFE Pre-Diagnostic Troubleshooting Procedure before proceeding. (Refer to
21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - 45RFE/545RFE - STANDARD PROCEDURE)
Theory of Operation
The Transmission Control System calculates the engine RPM by directly reading the engine crank position sensor.
It compares the calculated value to the engine speed sensor signal transmitted from the Engine Control System
over the controllers internal BUS. The calculated engine RPM is also comparedtoaminimumandamaximum
value.Note: Due to the integration of the Powertrain Control Module (PCM) and Transmission Control Mod-
ule (TCM), BUS communication between the modules is internal and unserviceable.
Diagnostic Test
1.CHECKFORRELATEDENGINEDTCS
NOTE: This is not a Transmission Input Speed Sensor DTC.
Ignition on, engine not running.
With the scan tool, read all Engine DTCs. This includes any active or storedor one trip DTCs.
Are there any engine RPM related DTCs present?
Ye s>>
Refer to the Powertrain category and perform the appropriate symptom.
Perform 45RFE/545RFE TRANSMISSION VERIFICATION TEST - VER 1. (Refer to 21- TRANSMIS-
SION/TRANSAXLE/AUTOMATIC - 45RFE/545RFE - STANDARD PROCEDURE)
No>>
Go To 2
2.CHECK IF DTC IS CURRENT
Ignition on, engine not running.
With a scan tool, read and record all DTC EVENT DATA.
Withthescantool,eraseallactiveandstoredtransmissionDTCs.(Note:it may be necessary to perform a battery
disconnect with the scan tool to clear DTC EVENT DATA.)
Using the DTC EVENT DATA, duplicate theconditions in which the original DTCset.
With the scan tool, read transmission and engine DTCs.
NOTE: Refer to all engine DTCs first in the following question.
Pick the answer below that best describes your findings, (this includes one trip failures).
Transmission DTC P0725 set
Using the schematics as a guide, check the Powertrain Control Module (PCM)terminals for corrosion,
damage, or terminal push out. Also check the Crank Position sensor and wiring. Pay particular attention
