TB: Transmission Control Switch (TCS)/Transmission Control Indicator Lamp(TCIL)

TB: Introduction See: TB: Transmission Control Switch (TCS) / Transmission Control Indicator Lamp (TCIL) - Introduction

TB1 CHECK TCS FUNCTION

DTC P1780

• Key on, engine off.
• Access the TCS PID.
• Cycle the TCS switch button, then hold it depressed for three seconds. Release the button
• Key off.

Did TCS PID reading switch from ON to OFF, and did reading indicate ON when button was held depressed?
Yes

• RERUN KOER Self-Test to cycle TCS.

No

• GO to TB2. FOR WINDSTAR, REFER to Automatic Transmission/ Transaxle.

TB2 CHECK VOLTAGE TO TCS

Note: Refer to the PCM connector pin numbers in the beginning of this pinpoint test.

• Disconnect PCM.
• Key on, engine off.
• Measure the voltage between the PCM harness connector pin and battery negative post while cycling the TCS several times.
• Key off.

Did the voltage cycle?
Yes

• REPLACE PCM (refer to Section 2, Flash Electrically Erasable Programmable Read Only Memory (EEPROM) See: Programming and Relearning\Flash Electrically Eraseable Programmable Read Only Memory - Flash EEPROM).

No

• GO to TB3

.

TB3 CHECK TCS CIRCUIT FOR SHORT TO GROUND IN HARNESS

• Disconnect TCS.
• Measure the resistance TCS circuit between PCM harness connector pin and battery negative post.

Is resistance greater than 10,000 ohms?
Yes

• GO to TB4

.

No

• REPAIR short circuit.

TB4 CHECK TCS CIRCUIT FOR OPEN IN HARNESS

• Measure the resistance of the TCS keypower between fuse junction panel and power side of the TCS harness connector.
• Measure resistance of TCS circuit between PCM harness connector pin and the transmission control switch harness connector.

Are both resistances less than 5.0 ohms?
Yes

• GO to TB5

.

No

• REPAIR open circuit.

TB5 CHECK TCS CIRCUIT FOR SHORTS TO POWER IN HARNESS

• Measure the resistance between TCS and VPWR circuits at the PCM harness connector.

Is resistance greater than 10,000 ohms?
Yes

• REPLACE damaged transmission control switch.

No

• REPAIR short circuit.

TB6 CHECK TCIL FUNCTION

• Key on, engine off.
• Cycle the transmission control switch (TCS).

Did the TCIL lamp change state?
Yes

• GO to Z1 See: Diagnostic Trouble Code Tests and Associated Procedures\SECTION 5: Pinpoint Tests\Z: Intermittent - Pinpoint Test

to check for an intermittent fault.

No

• GO to TB7

.

TB7 CHECK TCIL CIRCUIT FOR SHORT TO GROUND IN HARNESS

• Key off.
• Disconnect PCM.
• Key on, engine off.

Did the TCIL lamp change state?
Yes

• TCIL turns off when PCM is disconnected. REPLACE PCM (refer

to Section 2, Flash Electrically Erasable Programmable Read Only Memory (EEPROM) See: Programming and Relearning\Flash Electrically Eraseable Programmable Read Only Memory - Flash EEPROM).

No

• REPAIR short circuit between bulb and the TCIL Test Pin. VERIFY

a symptom no longer exists.

TB8 CHECK FOR DTC P1780

• Run Key On Engine Running (KOER) Self-Test.

Is DTC P1780 present?
Yes

• REPAIR DTC 1780. GO to TB1

.

No

• GO to TB9

.

TB9 CHECK VOLTAGE TO TCIL

Note: Refer to the PCM connector pin numbers in the beginning of this pinpoint test.

• Key off.
• Disconnect PCM.
• Key on, engine off.
• Measure voltage between TCIL circuit at PCM harness connector pin and battery negative post.

Are voltage readings greater than 2.0 volts?
Yes

• Using proper Wiring Diagram, verify integrity of wiring between

the TCIL indicator and the PCM harness connector pin. If no concern exists,
REPLACE PCM. (refer to Section 2, Flash Electrically Erasable Programmable Read Only Memory (EEPROM) See: Programming and Relearning\Flash Electrically Eraseable Programmable Read Only Memory - Flash EEPROM).
CYCLE TCS to check operation of TCIL.

No

• CHECK indicator bulb and fuse. If OK, open is in the wiring

between the Ignition switch and the TCIL Test Pin at the harness connector.
REPAIR as necessary.