| Table 1: | Shift Solenoid State Table |
| Table 2: | P0753 1-2 Shift Solenoid Circuit -- Electrical |
Circuit Description
The 1-2 Shift Solenoid Valve (1-2 SS Valve) controls fluid flow acting on the 1-2 shift valve. The solenoid is a normally-open valve that, in conjunction with the 2-3 Shift Solenoid Valve (2-3 SS Valve), allows four different shifting combinations (Refer to the Shift Solenoid State Table). The 1-2 SS Valve is attached to the valve body, within the transmission.
The solenoid receives ignition voltage through the fused circuit. The Powertrain Control Module (PCM) commands the solenoid ON or OFF by providing a ground path through circuit 1222.
When the PCM detects a continuous open, short to ground, or short to power in the 1-2 SS Valve circuit, then DTC P0753 sets. DTC P0753 is a type A DTC.
Conditions for Setting the DTC
| • | The ignition switch is in the RUN position. |
| • | The system voltage is 9-16 volts. |
| • | The PCM commands the solenoid ON, and the voltage remains high for 4.3 seconds. |
Action Taken When the DTC Sets
| • | The PCM illuminates the Malfunction Indicator Lamp (MIL). |
| • | The PCM commands maximum line pressure. |
| • | The PCM commands a soft landing to 2nd gear. |
| • | The PCM inhibits TCC engagement. |
| • | The PCM freezes shift adapts from being updated. |
| • | DTC P0753 is stored in the PCM history. |
Conditions for Clearing the MIL/DTC
| • | The PCM turns OFF the MIL after three consecutive trips without a failure reported. |
| • | A scan tool can clear the DTC from the PCM history. The PCM clears the DTC from the PCM history if the vehicle completes 40 warm-up cycles without a failure reported. |
| • | The PCM cancels the DTC default actions when the fault no longer exists and the ignition is OFF long enough in order to power down the PCM. |
Diagnostic Aids
| • | An open in circuit 439 will cause multiple DTCs to set. |
| • | Inspect the wiring for poor electrical connections at the PCM, the transmission 20-way connector, the 1-2 SS Valve 2-way connector and all other circuit connecting points for the following conditions: |
| - | A bent terminal |
| - | A backed out terminal |
| - | A damaged terminal |
| - | Poor terminal tension |
| - | A chafed wire |
| - | A broken wire inside the insulation |
| - | Moisture intrusion |
| - | Corrosion |
| • | When diagnosing for an intermittent short or open condition, massage the wiring harness while watching the test equipment for a change. |
Gear | 1-2 Shift Solenoid Valve | 2-3 Shift Solenoid Valve |
|---|---|---|
1st | ON | OFF |
2nd | OFF | OFF |
3rd | OFF | ON |
4th | ON | ON |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
-
DTCs P0758 and P1860 set if the power circuit is open.
-
This step tests the electrical operation of the solenoid.
-
This step tests the PCM and the wiring to the transmission.
-
This step tests circuit 1222 for a short to battery power.
-
This step verifies that the circuit has the correct resistance.
Step | Action | Value(s) | Yes | No | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
1 | Were you sent here from the Powertrain On-Board Diagnostic (OBD) System Check? | -- | ||||||||
Important: Before clearing the DTCs, use the scan tool in order to record the Freeze Frame and Failure Records for reference. Using the Clear Info function will erase the stored Freeze Frame and Failure Records from the PCM. Are DTCs P0758 and P1860 also set? | -- | |||||||||
3 |
Did you find the condition? | -- | ||||||||
4 | Inspect circuit 439 for a short to ground. Refer to General Electrical Diagnosis . Did you find and correct the condition? | -- | ||||||||
5 | Inspect circuit 839 for a short to ground. Refer to General Electrical Diagnosis . Did you find the condition? | -- | -- | |||||||
6 | Inspect circuit 439 for an open. Refer to General Electrical Diagnosis . Did you find and correct the condition? | -- | ||||||||
7 | Inspect circuit 839 for an open. Refer to General Electrical Diagnosis . Did you find the condition? | -- | -- | |||||||
Does the solenoid click when commanded ON and OFF? | -- | Go to Diagnostic Aids | ||||||||
Is the test lamp ON when you command the solenoid ON, and OFF when you command the solenoid OFF? | -- | |||||||||
10 | Is the test lamp always ON? | -- | ||||||||
11 |
Is the test lamp ON? | -- | ||||||||
12 | Inspect circuit 1222 for a short to ground. Refer to General Electrical Diagnosis . Did you find and correct the condition? | -- | -- | |||||||
13 | Is the test lamp always OFF? | -- | -- | |||||||
14 | Inspect circuit 1222 for an open. Refer to General Electrical Diagnosis . Did you find and correct the condition? | -- | ||||||||
Connect a test lamp from terminal A to a good ground. Is the test lamp ON? | -- | |||||||||
16 | Inspect circuit 1222 for a short to battery power. Refer to General Electrical Diagnosis . Did you find and correct the condition? | -- | -- | |||||||
Is the resistance within the specified range? | 19-31 ohms | |||||||||
18 | Is the resistance greater than the specified value? | 250 ohms | ||||||||
19 |
Refer to General Electrical Diagnosis . Did you find the condition? | -- | ||||||||
20 | Measure the resistance from terminal A to a good ground. Is the resistance less than the specified value? | 1000 ohms | ||||||||
21 | Inspect circuit 1222 for a short to ground. Refer to General Electrical Diagnosis . Did you find the condition? | -- | -- | |||||||
22 | Replace the automatic transmission wiring harness. Refer to the Transmission Unit Repair Manual, 4T40-E Section. Is the replacement complete? | -- | -- | |||||||
23 | Replace the 1-2 SS Valve. Refer to the Transmission Unit Repair Manual, 4T40-E Section. Is the replacement complete? | -- | -- | |||||||
24 | Replace the PCM. Refer to PCM Replacement/Programming . Is the replacement complete? | -- | -- | |||||||
25 | In order to verify your repair, perform the following procedure:
Has the test run and passed? | -- | System OK |
