Refer to
DIESEL PCM, AUTOMATIC TRANSMISSION
Circuit Description
The TCC normally closed brake switch supplies a B+ signal on CKT 420 to the PCM. The circuit is opened when the brakes are applied. The stop lamp/cruise control normally open brake switch supplies a B+ signal on CKT 820 to the PCM when the brake is applied. This is a type D DTC.
Conditions for Setting the DTC
| • | Switches disagree for 10 consecutive minutes. |
or
| • | TCC and cruise control brake switches are not toggling open and closed, during 6 brake applications on same ignition cycle. |
Action Taken When the DTC Sets
Fourth gear operation in hot mode, and cruise control operation.
Conditions for Clearing the MIL/DTC
| • | A History DTC will clear when forty consecutive warm-up cycles that the diagnostic does not fail (coolant temperature has risen 5°C (40°F) from start up coolant temperature and engine coolant temperature exceeds 71°C (160°F) that same ignition cycle. |
| • | Use of a Scan tool |
Diagnostic Aids
Refer to PCM Intermittent Diagnostic Trouble Codes or Performance. Check customer driving habits and/or unusual traffic conditions (i.e. stop and go, expressway traffic).
Test Description
Number(s) below refer to the step number(s) on the Diagnostic Table.
-
This test simulates brake switch closed or brakes OFF.
-
This test checks the feed circuit.
-
This test checks the feed circuit.
-
This test simulates a brake switch closed or the brakes ON.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 |
Important: Before clearing DTCs use the scan tool Capture Info to record freeze frame and failure records for reference, as data will be lost when Clear Info function is used. Was the Powertrain On-Board Diagnostic (OBD) System Check performed? | -- | ||
Does scan tool display Cruise Brake switch Closed and then Open when brake is released? | -- | |||
Apply brakes again. Does scan tool display Brake switch Open and then Closed when brake is released? | -- | |||
Is test light ON? | -- | |||
5 |
Is the test light ON? | -- | ||
Does scan tool display Cruise Brake switch Closed? | -- | |||
7 |
Is test light ON? | -- | ||
8 |
Does scan tool display Cruise Brake switch Closed? | -- | ||
9 | DTC is intermittent. If no additional DTCs are stored, refer to Diagnostic Aids. If additional DTCs were stored refer to the applicable DTC table(s) first. Are any additional DTCs stored? | -- | Go to the Applicable DTC Table | Go to Diagnostic Aids |
10 | Check normally open feed circuit (terminal B) for and open or short to ground. Is the action complete? | -- | -- | |
11 |
Is the action complete? | -- | ||
12 | Check normally open Cruise Brake switch signal circuit for and open or short to ground. Was a repair performed? | -- | ||
13 | Check the normally open Cruise Brake switch signal circuit for a poor connection at PCM? Was a repair performed? | -- | ||
14 | Check normally closed feed circuit (terminal F) for and open or short to ground. Is the action complete? | -- | -- | |
15 | Check normally closed Brake switch signal circuit for and open or short to ground. Was a repair performed? | -- | ||
16 | Check the normally closed Brake switch signal circuit for a poor connection at PCM? Was a repair performed? | -- | ||
17 | Replace stop lamp switch. Is the action complete? | -- | -- | |
18 | Replace the PCM. Important: The new PCM must be programmed. Refer to Powertrain Control Module Replacement/Programming . Is the action complete? | -- | -- | |
19 |
Does the Scan Tool indicate that the diagnostic Passed? | -- | ||
20 | Does the Scan tool display any additional undiagnosed DTCs? | -- | Go to the Applicable DTC Table | System OK |
