Circuit Description
The 1-2 Shift Solenoid Valve (1-2 SS Valve) controls the fluid flow acting on the 1-2 and 3-4 shift valves. The 1-2 SS Valve is a normally-open exhaust valve that is used with the 2-3 Shift Solenoid Valve in order to allow four different shifting combinations. The solenoid attaches to the control valve body within the transmission. The 1-2 SS Valve receives ignition voltage through circuit 339. The Powertrain Control Module (PCM) controls the solenoid by providing the ground path on circuit 1222.
When the PCM detects a continuous open or short to ground in the 1-2 SS Valve circuit or the 1-2 SS Valve, then DTC P0753 sets. DTC P0753 is a type A DTC.
Conditions for Setting the DTC
| • | The system voltage is 10-18 volts. |
| • | The engine speed is greater than 450 RPM for 8 seconds. |
| • | Not in fuel cutoff. |
| • | All of the above conditions are met for 5 seconds and either of the following fail conditions occurs for 5 seconds: |
| - | The PCM commands the solenoid ON and the voltage input remains high (B+). |
| - | The PCM commands the solenoid OFF and the voltage input remains low (0 volts). |
Action Taken When the DTC Sets
| • | The PCM illuminates the Malfunction Indicator Lamp (MIL). |
| • | The PCM commands D2 line pressure. |
| • | The PCM inhibits 3-2 downshifts if the vehicle speed is greater than 48 km/h (30 mph). |
| • | The PCM freezes shifts adapts from being updated. |
| • | DTC P0753 stores in 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
| • | Inspect the wiring at the PCM, the transmission 20-way connector and at 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. |
| Refer to Shift Solenoid Valve State and Gear Ratio . |
| • | An open ignition feed circuit can cause multiple DTCs to set. |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
-
This step tests for power to the 1-2 SS Valve from the ignition through the fuse.
-
This step tests the ability of the PCM and the wiring to control the ground circuit.
-
This step measures the resistance of the Automatic Transmission Wiring Harness Assembly and the 1-2 SS Valve.
Step | Action | Value(s) | Yes | No | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
1 | Was the Powertrain On-Board Diagnostic (OBD) System Check performed? | -- | Go to Powertrain OBD System Check | |||||||
2 |
Important: Before clearing the DTC(s), 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 DTC(s) P0740, P0758, P0785 and P1860 also set? | -- | ||||||||
3 |
Refer to General Electrical Diagnosis Procedures. Did you find a short to ground condition? | -- | ||||||||
Is the test lamp ON? | -- | |||||||||
Is the test lamp ON when the 1-2 SS Valve is commanded ON, and OFF when commanded OFF? | -- | |||||||||
6 | Repair the open or short to ground in ignition feed circuit 339 (PNK) to the 1-2 SS Valve. Refer to General Electrical Diagnosis Procedures. Did you find and correct an open or short to ground condition? | -- | -- | |||||||
7 | Monitor the test lamp status. Was the test lamp OFF at all times? | -- | ||||||||
8 | Inspect circuit 1222 (LT GRN) for an open. Repair the circuit if necessary. Refer to General Electrical Diagnosis Procedures. Did you find an open condition? | -- | ||||||||
9 | Was the test lamp ON at all times? | -- | -- | |||||||
10 | Inspect circuit 1222 (LT GRN) for a short to ground. Repair the circuit if necessary. Refer to General Electrical Diagnosis Procedures. Did you find a short to ground condition? | -- | ||||||||
11 | Replace the PCM. Refer to PCM/TAC Module Replacement. Is the replacement complete? | -- | -- | |||||||
Is the resistance within the range indicated? | 19-31 ohms | |||||||||
13 |
Is the resistance within the range indicated? | 19-31 ohms | ||||||||
14 | Using J 39200 DMM, measure the resistance between terminals A and E and ground. Are both readings greater than the specified value? | 250 K ohms | Go to Diagnostic Aids | |||||||
15 |
Are both readings greater than the specified value? | 250 K ohms | ||||||||
16 | Replace the Automatic Transmission Wiring Harness Assembly. Refer to TCC PWM Solenoid, TCC Solenoid, and Wiring Harness. Is the replacement complete? | -- | -- | |||||||
17 | Replace the 1-2 SS Valve. Refer to Control and Shift Solenoids Replacement. Is the replacement complete? | -- | -- | |||||||
18 | In order to verify your repair, perform the following procedure:
Has the test run and passed? | -- | System OK |
