The service engen soon light is on it a 1997 Chevrolet truck K1500 4WD pickup 5.7 8Cyl Emissions-related Powertrain DTCs, Mode 3: Electronic Control Unit ID: 10 P1870 Manufacturer specifc code: Continously Monitored systems DTCs, mode 7 No diagnostic trouble codes recorded

ETC - electronic throttle control problem .

P0606 - Powertrain Control Module (PCM) Internal Communication Error Description: P0606 indicates a register readback (PCM internal communications) error. Possible Causes:

• Damaged PCM.

Diagnostic Aids: Internal PCM failure. Install a new PCM.
For Electronic Throttle Control applications, an internal PCM failure, or an ETC system FMEM condition exists. Repairing the other DTCs can fix the P0606. Application Key On Engine Off Key On Engine Running Continuous Memory Vehicles With Electronic Throttle Control (ETC) The DTC is an indication of a failure mode in the electronic throttle control system, which includes the accelerator pedal position (APP) sensor, electronic throttle body (ETB), and powertrain control module (PCM). It is accompanied by other DTCs which provide repair direction. Diagnose and repair those DTCS, and the P0606 will not be reset. All others Make sure to check for aftermarket performance products before installing a new powertrain control module (PCM). If it is necessary to install a new PCM, refer to Section 2, Flash Electrically Erasable Programmable Read Only Memory (EEPROM).

Did you have it checked for code's ?
P0720 OSS Insufficient input from OSS sensor. PCM detected a loss of OSS signal during operation. Harsh shifts, and abnormal shift schedule. (MIL on) Will display Check Transmission message. Go To Pinpoint Test G . P0721 OSS Output shaft speed sensor signal noisy. PCM has detected an erratic OSS signal. Harsh shifts, and abnormal shift schedule. Go To Pinpoint Test G . P0722 OSS Output shaft speed sensor signal intermittent. PCM has detected an erratic or no OSS signal. Will display Check Transmission message. Go To Pinpoint Test G . Hooking up a scan tool an checking DTC'S an viewing sensor input data to the computer is the correct way to diagnose , not guess OSS , an just replace parts . Your best bet , take it to a qualified repair shop.
SECTION 307-01: Automatic Transaxle/Transmission - 4F50N 2004 Taurus/Sable Workshop Manual DIAGNOSIS AND TESTING Procedure revision date: 07/02/2003 Transaxle Drive Cycle Test NOTE: Always drive the vehicle in a safe manner according to driving conditions and obey all traffic laws.
After carrying out the Quick Test, use the following Transaxle Drive Cycle Test for checking continuous codes:
NOTE: The Transaxle Drive Cycle Test must be followed exactly. Malfunctions must occur 4 times consecutively for shift error DTC code to be set, and five times consecutively for continuous torque converter clutch code to set.
NOTE: When carrying out the Transaxle Drive Cycle Test, see the solenoid operation chart for correct solenoid operation. Refer to Pinpoint Tests - Non OSC Equipped Vehicles in this section.

1. Record and then erase Quick Test codes.

1. Warm engine to normal operating temperature.

1. Make sure transmission fluid level is correct.

1. With transaxle in OVERDRIVE, moderately accelerate from stop to 80 km/h (50 mph). This allows the transaxle to shift into 4th gear. Hold speed and throttle opening steady for minimum of 15 seconds.

1. With transaxle in 4th gear and maintaining steady speed and throttle opening, lightly apply and release brake (to operate stoplamps). Then hold speed and throttle steady for additional 5 seconds minimum.

1. Brake to a stop and remain stopped for minimum of 20 seconds.

1. Repeat Steps 4 through 6 at least 5 times.

1. Carry out Quick Test and record continuous codes.

• If DTCs are present, refer to Diagnostic Trouble Code (DTC) Charts in this section. Service all non-transaxle DTCs first as they can directly affect the operation of the transaxle. Repeat the Quick Test and Road Test to verify the correction. Erase DTCs, carry out drive cycle, and repeat the Quick Test after completing service on the DTCs.
• If the continuous test passes (system pass) and a concern is still present, refer to Diagnosis By Symptom in this section check OASIS, and TSBs for diagnostic concern.

After On-Board Diagnostics
NOTE: The vehicle wiring harness, powertrain control module and non-transaxle sensors may affect transaxle operations. Service these concerns first.
After the On-Board Diagnostic procedures are completed, service all DTCs.
Begin with non-transaxle related DTCs, then service any transaxle related DTCs. Refer to the Diagnostic Trouble Code (DTC) Charts for information on Condition and Symptoms. This chart will be helpful in referring to the correct manual(s) and to aid in diagnosing internal transaxle concerns and external non-transaxle inputs. The pinpoint tests are used in diagnosing electrical concerns of the transaxle. Make sure that the vehicle wiring harness and the powertrain control module are diagnosed as well. Refer to the Powertrain Control/Emissions Diagnosis (PC/ED) manual for diagnosing non-transaxle electronic components. The diagnostic routine hydraulic/mechanical charts will help in diagnosing internal transaxle concerns and external non-transaxle inputs.
Before Pinpoint Tests
NOTE: Prior to entering pinpoint tests, check the powertrain control module (PCM) wiring harness for correct connections, bent or broken pins, corrosion, loose wires, correct routing, correct seals and their condition. Check the PCM, sensors and actuators for damage. Refer to the Powertrain Control/Emissions Diagnosis (PC/ED) manual.
NOTE: If a concern still exists after electrical diagnosis has been carried out, refer to Diagnosis By Symptom in this section.
If DTCs appear while carrying out the on-board diagnostics, refer to the Diagnostic Trouble Code (DTC) Charts in this section for the appropriate repair procedure. Prior to entering pinpoint tests, refer to any TSBs and OASIS messages for transaxle concerns.

Here is what the troubleshooting guide says:
WHEN MONITORED
Ignition on.

SET CONDITION
The fuel volume message the PCM is receiving is implausible. The circuit is continuously monitored.

POSSIBLE CAUSES

• CAN B open or shorted
• Cluster module
• Front control module
• PCM

Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding.

Theory of Operation
The Front ControlModule isn't receiving a fuel volume signal over CAN B from the ClusterModule. The FCM has to send the PCM a fuel volume signal over CAN C. The signal the FCM sends over CAN C is implausible.

DIAGNOSTIC TEST



1. ACTIVE DTC Ignition on, engine not running.
With a scan tool read DTCs.

Q: Is the DTC active at this time?

YES: Go To 2
NO: Refer to the INTERMITTENT CONDITION Diagnostic Procedure. Perform the POWERTRAIN VERIFICATION TEST.



2. CAN B BUS HARDWARE DTCS ALSO ACTIVE
With a scan tool check for DTCs in the FCM. Q: Are any CAN B Hardware related DTCs active at this time?

YES: (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROLMODULES - DIAGNOSIS AND TESTING) for the appropriate diagnostic procedures. Perform BODY VERIFICATION TEST - VER 1.
NO: Replace and program the Powertrain Control Module per Service Information. Perform the POWERTRAIN VERIFICATION TEST.

Sorry, but it looks like it could be a computer problem.

Service Vehicle Soon
The driver information center (DIC) illuminates the SERVICE VEHICLE SOON indicator when the powertrain control module (PCM) or the engine control module (ECM) detects certain malfunctions that are not related to the emissions system. You should have it checked for DTC'S - diagnostic trouble codes ! Unless related to a emission problem the check engine light won't come on . But can still set a code in the PCM

You need to have it checked for DTC'S - diagnostic trouble codes to see what the problem is ,then diagnosed , then fixed ! Then the light's will go off ! This means taking it to a qualified repair shop .
SERVICE VEHICLE SOON
The IPC illuminates the SERVICE VEHICLE SOON message in the DIC when the powertrain control module (PCM) detects certain malfunctions that are not related to the emissions system. The IPC receives a class 2 message requesting illumination from the PCM.

Error Code: P0441
Fault Location:
Evaporative Emission (EVAP) System - Incorrect Flow Detected
Possible Cause:
Malfunction Indicator Lamp (MIL) active.
- Purge control VSV connector disconnected.
- Evaporative Emission (EVAP) Canister Purge Regulator Valve is faulty/jammed.
- Evaporative Emission (EVAP) Canister Purge Solenoid Valve faulty/jammed.
- Evaporative Emission (EVAP) Canister Sealing faulty.
- Pipes between Tank Breathing and Throttle Body leaky/blocked.
- Hose connection(s).
- Intake leak.
Solutions:
- Check Evaporative Emission (EVAP) Canister Purge Regulator Valve.
- Perform Output Test.
- Check Evaporative Emission (EVAP) Canister Purge Solenoid Valve.
- Check Evaporative Emission (EVAP) Canister.
- Perform Basic Setting.
- Check Pipes between Tank Breathing and Throttle Body.

There is a diagnostic procedure in the factory service repair manual for engine light lit ,no codes . Did you take it to ford dealer ? MIL - is referring to check engine , service engine soon etc...

• MIL always on when engine is running (no DTCs):
• MIL circuits

• For Focus, Mustang, Town Car, Continental, LS6/LS8, Escape, Windstar, F-150, Expedition and Navigator/Blackwood:
• Instrument Cluster, Section 413-01 of the Workshop Manual.
• All Others:
• GO to NB1

SERVICE ENGINE SOON indicator After the engine is started, the SERVICE ENGINE SOON indicator will prove out for a duration of three seconds. If the instrument cluster does not receive a message from the PCM within five seconds, the instrument cluster will illuminate the SERVICE ENGINE SOON indicator and log a diagnostic trouble code (DTC).

• An indicator is inoperative/always on - SERVICE ENGINE SOON

• Circuitry.
• Bulb.
• Instrument cluster.
• PCM.

• GO to Pinpoint Test P .

PINPOINT TEST P: AN INDICATOR IS INOPERATIVE/ALWAYS ON - SERVICE ENGINE SOON CONDITIONS DETAILS/RESULTS/ACTIONS P1 CARRY OUT THE INSTRUMENT CLUSTER SERVICE ENGINE SOON INDICATOR ACTIVE COMMAND Trigger the HEC active command MIL.

• Did the SERVICE ENGINE SOON indicator illuminate?

Yes REFER to Powertrain Control/Emissions Diagnosis (PC/ED) manual.

No INSTALL a new instrument cluster; REFER to Instrument Cluster . CLEAR the DTCs. REPEAT the self-test.

go to auto zone and they should read the code for free and point you in the the direction to fix your problems what ever code is first fix that first then do the next thing

In the Grand Cherokee WJ, the MIL gives an indication to the vehicle operator when the Powertrain Control Module (PCM) has recorded a Diagnostic Trouble Code (DTC) for an On-Board Diagnostics II (OBDII) emissions-related circuit or component malfunction. The MIL is controlled by a transistor on the instrument cluster circuit board based upon cluster programming and electronic messages received by the cluster from the PCM over the Programmable Communications Interface (PCI) data bus.

Check this procedure for Retrieving codes.

After, noted this codes, check what means here Dodge/Chrysler/Jeep/Plymouth OBD-II Trouble Codes

After three good trips the MIL is extinguished and the Task Manager automatically switches the trip counter to a warm-up cycle counter. DTCs are automatically erased following 40 warm-up cycles if the component does not fail again. Erasing codes.

Good luck (remember comment and rated this).

Hi:
There are hundreds of things that trip that light. You need to have your vehicle codes scanned to see what has caused it. Most auto parts stores will do this for free. It could be something as simple as a loose gas cap, but this is an easy way to figure it out!