| Table 1: | Shift Solenoid Valve State and Gear Ratio 4L60-E |
| Table 2: | DTC P0753 1-2 Shift Solenoid Valve - Electrical |
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 valve. The solenoid is a normally-open exhaust valve. The combination of the 2-3 Shift Solenoid Valve and the 1-2 SS Valve allows four different shifting combinations. The solenoid attaches to the control valve body within the transmission. Circuit 439 supplies ignition voltage directly to the 1-2 SS Valve. The PCM controls the solenoid by providing a ground path through circuit 1222.
When the PCM detects a continuous open or a 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 ignition is ON. |
| • | The system voltage is 10-17 volts. |
| • | The PCM commands the solenoid ON and the voltage remains high (B+). |
| • | The PCM commands the solenoid OFF and the voltage remains low (0 volts). |
| • | All conditions met for 5 seconds |
Action Taken When the DTC Sets
| • | The PCM commands maximum line pressure |
| • | The PCM freezes shift adapts from being updated. |
| • | If in hot mode, force the TCC on in 3rd and 4th gear when the brake is not applied and downshift is not requested. |
| • | The PCM inhibits downshifts to 2nd when the speed is greater than 30 mph. |
| • | The PCM illuminates the Malfunction Indicator Lamp (MIL) |
Conditions for Clearing the MIL/DTC
| • | The PCM turns OFF the MIL after three consecutive ignition cycles 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 for any poor electrical connections at the PCM. Inspect the wiring at the TCC brake switch. Look 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 |
| • | When diagnosing for an intermittent short or an open condition, massage the wiring harness while watching the test equipment for changes. |
| • | An open feed circuit can set multiple DTCs. |
Gear | 1-2 Shift Solenoid | 2-3 Shift Solenoid | Gear Ratio |
|---|---|---|---|
1 | ON | ON | 3.059:1 |
2 | OFF | ON | 1.625:1 |
3 | OFF | OFF | 1.000:1 |
4 | ON | OFF | 0.696:1 |
Test Description
The numbers below refer to the Step numbers on the diagnostic table.
-
This step verifies that the 1-2 SS Valve and the Automatic Transmission Wiring Harness are functioning normally.
-
This step verifies that the ignition supplies power to the 1-2 SS Valve through the PCM IGN fuse.
-
This step verifies that the valve's resistance is within specifications.
Step | Action | Value(s) | Yes | No | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
1 | Was the Powertrain On-Board Diagnostic (OBD) System Check performed? | -- | Go to Powertrain On Board Diagnostic (OBD) System Check , Section 6 | |||||||
2 |
Important: Before clearing the DTCs, use the scan tool in order to record the Freeze Frame and Failure Records for reference. The Clear Info function will erase the data. Have DTCs P0753, P0758, P1860, P1864, and P1886 set? | -- | ||||||||
3 |
Refer to Electrical Diagnosis, Section 8. Did you find and correct a problem? | -- | -- | |||||||
Using the scan tool, command the 1-2 SS Valve ON and OFF three times while listening to the bottom of the transmission pan (a stethoscope may be necessary). Did the solenoid click when commanded? | -- | |||||||||
5 | Inspect every connection at the PCM and at the transmission 20-way harness for the following conditions:
Did you find and correct a problem? | -- | Go to Diagnostic Aids | |||||||
Did the test lamp Illuminate? | -- | |||||||||
7 |
Important: Ground Pin R of the Jumper Harness. Does the test lamp illuminate when you command the solenoid valve ON, and turn OFF when you command the solenoid valve OFF? | -- | ||||||||
8 | Repair the open in the ignition feed circuit 439 to the 1-2 SS Valve. Refer to Electrical Diagnosis, Section 8. Did you find and correct a problem? | -- | -- | |||||||
9 | Monitor the test lamp. Was the test lamp OFF continuously? | -- | ||||||||
10 |
Did you find and correct a problem? | -- | ||||||||
11 | Was the test lamp illuminated continuously? | -- | -- | |||||||
12 |
Refer to Electrical Diagnosis, Section 8. Did you find and correct a problem? | -- | ||||||||
13 | Inspect the PCM connector for the following conditions:
Did you find and correct a problem? | -- | ||||||||
14 |
Are both readings greater than the specified value? | 250 kohms | ||||||||
15 |
Is the resistance within the specified range? | 19-31ohms | Go to Diagnostic Aids | |||||||
Is the resistance within the specified range? | 19-31ohms | |||||||||
17 |
Refer to Electrical Diagnosis, Section 8. Did you find and correct a problem? | -- | -- | |||||||
18 |
Are both readings greater than the specified value? | 250 kohms | ||||||||
19 |
Refer to Electrical Diagnosis, Section 8. Did you find and correct a problem? | -- | -- | |||||||
20 | Replace the 1-2 SS Valve. Refer to 1-2 Shift Solenoid Valve Replacement, in On-Vehicle Service. Is the replacement complete? | -- | -- | |||||||
21 | Replace the PCM. Refer to Powertrain Control Module Replacement/Programming , Section 6. Is the replacement complete? | -- | -- | |||||||
22 |
Has the test run and passed? | -- | System OK |
