Circuit Description
The 1-2 shift solenoid (SS) valve controls the fluid flow acting on the 1-2 and 3-4 shift valves. The solenoid is a normally-open exhaust valve. With the 2-3 SS valve, the 1-2 SS valve allows 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 1020. The vehicle control module (VCM) controls the solenoid by providing the ground path on circuit 1222.
When the VCM 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 Running the DTC
| • | The system voltage is 10-19 volts. |
| • | The engine speed is greater than 450 RPM for 5 seconds. |
| • | The engine is not in fuel cutoff. |
Conditions for Setting the DTC
DTC P0753 sets if one of the following conditions occurs for 5 seconds:
Condition 1
The VCM commands the solenoid ON and the voltage feedback remains high (B+).
Condition 2
The VCM commands the solenoid OFF and the voltage feedback remains low (0 volts).
Action Taken When the DTC Sets
| • | The VCM illuminates the malfunction indicator lamp (MIL). |
| • | The VCM commands D2 line pressure. |
| • | The VCM inhibits 3-2 downshifts if the vehicle speed is greater than 48 km/h (30 mph). |
| • | The VCM freezes shift adapts from being updated. |
| • | The VCM records the operating conditions when the Conditions for Setting the DTC are met. The VCM stores this information as Freeze Frame and Failure Records. |
| • | The VCM stores DTC P0753 in VCM history. |
Conditions for Clearing the MIL/DTC
| • | The VCM turns OFF the MIL during the third consecutive trip in which the diagnostic test runs and passes. |
| • | A scan tool can clear the MIL/DTC. |
| • | The VCM clears the DTC from VCM history if the vehicle completes 40 warm-up cycles without an emission-related diagnostic fault occurring. |
| • | The VCM cancels the DTC default actions when the fault no longer exists and/or the ignition switch is OFF long enough in order to power down the VCM. |
Diagnostic Aids
| • | Inspect the wiring at the VCM, the transmission connector and all other circuit connecting points for the following conditions: |
| - | A backed out terminal |
| - | A damaged terminal |
| - | Reduced 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 the Shift Solenoid Valve State and Gear Ratio table. |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
-
This step tests the function of the 1-2 SS valve and the automatic transmission (AT) wiring harness assembly.
-
This step tests for power to the 1-2 SS valve from the ignition through the fuse.
-
This step tests the ability of the VCM and of the wiring to control the ground circuit.
-
This step measures the resistance of the AT wiring harness assembly and of 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 On Board Diagnostic (OBD) System Check in Engine Controls | |||||||||
2 |
Important: Before clearing the DTC, use the Scan Tool in order to record the Freeze Frame and Failure Records. Using the Clear Info function erases the Freeze Frame and Failure Records from the VCM. Are any of the following DTCs also set?
| -- | ||||||||||
3 | Inspect the TRANS fuse for an open. Refer to General Electrical Diagnosis in Wiring Systems. Is the fuse open? | -- | ||||||||||
Using the transmission output control function on 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? | -- | Go to Diagnostic Aids | ||||||||||
Refer to Automatic Transmission Inline Harness Connector End View . Is the test lamp ON? | -- | |||||||||||
Refer to Automatic Transmission Inline Harness Connector End View . Does the test lamp illuminate when you command the shift solenoid ON, and does the test lamp turn off when you command the shift solenoid OFF? | -- | |||||||||||
7 | Is the test lamp always ON? | -- | ||||||||||
Refer to Automatic Transmission Inline Harness Connector End View . Is the resistance within the specified range? | 19-31 ohms | |||||||||||
9 | Measure the resistance from terminal A to ground, and from terminal E to ground. Are both readings greater than the specified value? | 250 K ohms | Go to Diagnostic Aids | |||||||||
10 |
Are both readings greater than the specified value? | 19-31 ohms | ||||||||||
11 |
Is the resistance within the specified range? | 250 K ohms | ||||||||||
12 |
Important: The condition that affects this circuit may exist in other connecting branches of the circuit. Refer to Power Distribution Schematics in Wiring Systems for complete circuit distribution. Refer to Circuit Testing in Wiring Systems. Refer to Wiring Repairs in Wiring Systems. Did you find a short to ground? | -- | ||||||||||
13 |
Important: The condition that affects this circuit may exist in other connecting branches of the circuit. Refer to Power Distribution Schematics in Wiring Systems for complete circuit distribution. Inspect circuit 839 (RED) of the AT wiring harness assembly for a short to ground. Refer to Circuit Testing in Wiring Systems. Did you find a short to ground? | -- | ||||||||||
14 |
Is the replacement complete? | -- | -- | |||||||||
15 |
Important: The condition that affects this circuit may exist in other connecting branches of the circuit. Refer to Power Distribution Schematics in Wiring Systems for complete circuit distribution. Repair the open in ignition feed circuit 1020 (PNK) to the 1-2 SS valve. Refer to Wiring Repairs in Wiring Systems. Is the repair complete? | -- | -- | |||||||||
16 |
Refer to Circuit Testing in Wiring Systems. Refer to Wiring Repairs in Wiring Systems. Did you find a short to ground? | -- | ||||||||||
17 |
Refer to Circuit Testing in Wiring Systems. Refer to Wiring Repairs in Wiring Systems. Did you find an open or a short to power? | -- | ||||||||||
18 | Replace the AT wiring harness assembly. Refer to Valve Body . Is the replacement complete? | -- | -- | |||||||||
19 | Replace the 1-2 SS valve. Refer to Valve Body . Is the replacement complete? | -- | -- | |||||||||
20 | Replace the VCM. Refer to VCM Replacement/Programming in Engine Controls. Is the replacement complete? | -- | -- | |||||||||
21 | Perform the following procedure in order to verify the repair:
Has the test run and passed? | -- | System OK |
