Circuit Description
The 1-2 shift solenoid (SS) valve controls the fluid flow of the 1-2 and the 3-4 shift valves. The 1-2 SS valve is a normally-open exhaust valve that is used with the 2-3 SS valve to allow for four different shifting combinations. The 1-2 SS valve attaches to the control valve body within the transmission. The ignition voltage goes directly to the 1-2 SS valve. The PCM controls the 1-2 SS valve by providing the ground path through the 1-2 shift solenoid valve control circuit.
When the powertrain control module (PCM) detects a continuous open or short in the 1-2 SS valve circuit or the 1-2 SS valve, then DTC P0753 sets. DTC P0753 is a type C DTC. For California emissions vehicles and vehicles under 8,600 GVW, DTC P0753 is a type A DTC.
Conditions for Running the DTC
| • | The system voltage is 8-18 volts. |
| • | The engine is running for greater than 7 seconds. |
Conditions for Setting the DTC
All conditions for running the DTC are met, and either of the following conditions occur for 4.3 out of 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. |
Action Taken When the DTC Sets
| • | For California emission equipped vehicles, the PCM illuminates the malfunction indicator lamp (MIL) during the second consecutive trip in which the Conditions for Setting the DTC are met. For Federal emission equipped vehicles, the MIL is not illuminated. |
| • | The PCM commands maximum line pressure. |
| • | The PCM freezes shift adapts. |
| • | The PCM inhibits 3-2 downshifts above 40 km/h (25 mph). |
| • | The PCM records the operating conditions when the Conditions for Setting the DTC are met. The PCM stores this information as Freeze Frame, California only, and Failure Records, California and Federal. |
| • | The PCM stores the DTC P0753 in PCM history during the second consecutive trip, California, or the first trip, Federal, in which the Conditions for Setting the DTC are met. |
Conditions for Clearing the MIL/DTC
| • | For California emissions, the PCM 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. |
| • | For California emissions, the PCM clears the DTC from PCM history if the vehicle completes 40 warm-up cycles without an emission related diagnostic fault occurring. |
| • | For Federal emissions, the PCM clears the DTC from PCM history if the vehicle completes 40 warm-up cycles without a non-emission related diagnostic fault occurring. |
| • | The PCM cancels the DTC default actions when the fault no longer exists and the ignition switch is OFF long enough in order to power down the PCM. |
Diagnostic Aids
| • | An open ignition feed on the Off/Run/Crank voltage circuit (CKT 1020) can cause multiple DTCs to set. Refer to Shift Solenoid Valve State and Gear Ratio . |
| • | DTC P0753 defaults to an elevated line pressure condition which may result in partial TCC apply. This may produce an idle surge that could stall the engine. |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
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This step tests the function of the 1-2 SS valve and the internal wiring harness.
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This step tests the power to the 1-2 SS valve from the ignition.
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This step tests the ability of the PCM and the wiring to control the ground circuit.
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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 | Did you perform the Diagnostic System Check - Engine Controls? | -- | Go to Step 2 | Go to Diagnostic System Check - Engine Controls in Engine Controls - 6.0L or Diagnostic System Check - Engine Controls in Engine Controls - 8.1L | ||||||
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 PCM. Is DTC P0758 or P1860 also set? | -- | Go to Step 3 | Go to Step 4 | ||||||
3 | Inspect the IGN 0 fuse for an open. Refer to Circuit Protection - Fuses in Wiring Systems. Is the fuse open? | -- | Go to Step 12 | Go to Step 5 | ||||||
Use the scan tool in order to 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. Does the solenoid click when commanded? | -- | Go to Intermittent Conditions in Engine Controls - 6.0L or Intermittent Conditions in Engine Controls - 8.1L | Go to Step 5 | |||||||
Does the test lamp illuminate? | -- | Go to Step 6 | Go to Step 15 | |||||||
Does the test lamp turn ON and OFF with each command? | -- | Go to Step 8 | Go to Step 7 | |||||||
7 | Is the test lamp always ON? | -- | Go to Step 16 | Go to Step 17 | ||||||
Does the resistance measure within the specified range? | 19-31 ohms | Go to Step 9 | Go to Step 10 | |||||||
9 | Measure the resistance from terminal A to ground, and from terminal E to ground. Do both readings measure greater than the specified value? | 250 K ohms | Go to Intermittent Conditions in Engine Controls - 6.0L or Intermittent Conditions in Engine Controls - 8.1L | Go to Step 11 | ||||||
10 |
Does the resistance measure within the specified range? | 19-31 ohms | Go to Step 18 | Go to Step 19 | ||||||
11 |
Do both readings measure greater than the specified value? | 250 K ohms | Go to Step 18 | Go to Step 19 | ||||||
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. Test the Ignition 0 voltage circuit (CKT 1020) of the 1-2 SS valve for a short to ground between the fuse block and the AT inline 20-way connector. Refer to Testing for Short to Ground and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 21 | Go to Step 13 | ||||||
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. Test the Ignition 1 voltage circuit (CKT 839) of the 1-2 SS valve for a short to ground between the AT inline 20-way connector and the 1-2 SS valve. Refer to Testing for Short to Ground in Wiring Systems. Did you find a short to ground condition? | -- | Go to Step 18 | Go to Step 14 | ||||||
14 |
Did you complete the replacement? | -- | Go to Step 21 | -- | ||||||
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. Test the Ignition 0 voltage circuit (CKT 1020) of the 1-2 SS valve for an open. Refer to Testing for Continuity and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 21 | -- | ||||||
16 | Test the control circuit (CKT 1222) of the 1-2 SS valve for a short to ground between the PCM connector C2 and the AT inline 20-way connector. Refer to Testing for Short to Ground and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 21 | Go to Step 20 | ||||||
17 | Test the control circuit (CKT 1222) of the 1-2 SS valve for an open or short to power between the PCM connector C2 and the AT inline 20-way connector. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 21 | Go to Step 20 | ||||||
18 | Replace the AT wiring harness assembly. Refer to Valve Body and Pressure Switch Replacement . Did you complete the replacement? | -- | Go to Step 21 | -- | ||||||
19 | Replace the 1-2 SS valve. Refer to Valve Body and Pressure Switch Replacement . Did you complete the replacement? | -- | Go to Step 21 | -- | ||||||
20 | Replace the PCM. Refer to Powertrain Control Module Replacement in Engine Controls - 6.0L or Powertrain Control Module Replacement in Engine Controls - 8.1L. Did you complete the replacement? | -- | Go to Step 21 | -- | ||||||
21 | Perform the following procedure in order to verify the repair:
Has the test run and passed? | -- | Go to Step 22 | Go to Step 2 | ||||||
22 | With the scan tool, observe the stored information, capture info and DTC info. Does the scan tool display any DTCs that you have not diagnosed? | -- | Go to Diagnostic Trouble Code (DTC) List in Engine Controls - 6.0L or Diagnostic Trouble Code (DTC) List in Engine Controls - 8.1L | System OK |
