Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
2012 Scion xB Automatic TransFACTORY OEM SERVICE PROCEDURE
Problem Symptoms Table
HINT:
- Use the tables below to help determine the cause of the problem symptom. The potential causes of the symptoms are listed in order of probability in the "Suspected Area" column of the tables. Check each symptom by checking the suspected areas in the order they are listed. Replace parts as necessary.
- The Matrix Chart is divided into 2 chapters. When troubleshooting, check Chapter 1 first. If instructions are given in Chapter 1 to proceed to 2, proceed as instructed.
- If the instruction "Proceed to next circuit inspection shown in problem symptoms table" is given in the flowchart for each circuit, proceed to the next suspected area in the table.
- If the problem still occurs even though there are no malfunctions in any of the circuits, check the ECM and replace it if necessary.
CHAPTER 1: ELECTRICAL CIRCUIT MATRIX CHART
| Symptom | Suspected Area | See |
|---|---|---|
| No up-shift (From 1st to 2nd) | ECM | Refer to ELECTRONIC CIRCUIT INSPECTION PROCEDURE |
| No up-shift (From 2nd to 3rd) | ECM | Refer to ELECTRONIC CIRCUIT INSPECTION PROCEDURE |
| No up-shift (From 3rd to 4th) | Park/Neutral position switch circuit* | Refer to DTC P0705: Transmission Range Sensor Circuit Malfunction (PRNDL Input) |
| ECM | Refer to ELECTRONIC CIRCUIT INSPECTION PROCEDURE | |
| No down-shift (From 4th to 3rd) | ECM | Refer to ELECTRONIC CIRCUIT INSPECTION PROCEDURE |
| No down-shift (From 3rd to 2nd) | ECM | Refer to ELECTRONIC CIRCUIT INSPECTION PROCEDURE |
| No down-shift (From 2nd to 1st) | ECM | Refer to ELECTRONIC CIRCUIT INSPECTION PROCEDURE |
| No lock-up or no lock-up off | ECM | Refer to ELECTRONIC CIRCUIT INSPECTION PROCEDURE |
| Shift point too high or too low | ECM | Refer to ELECTRONIC CIRCUIT INSPECTION PROCEDURE |
| No gear change by shifting into "+" or "-" while the shift lever is in S | Transmission control switch circuit | Refer to Transmission Control Switch Circuit |
| ECM | Refer to ELECTRONIC CIRCUIT INSPECTION PROCEDURE | |
| Up-shift to 4th from 3rd while engine is cold | Engine coolant temperature sensor circuit* | Refer to DIAGNOSTIC TROUBLE CODE CHART |
| ECM | Refer to ELECTRONIC CIRCUIT INSPECTION PROCEDURE | |
| Harsh engagement (From N to D) | ECM | Refer to ELECTRONIC CIRCUIT INSPECTION PROCEDURE |
| Harsh engagement (lock-up) | ECM | Refer to ELECTRONIC CIRCUIT INSPECTION PROCEDURE |
| Harsh engagement (any driving position) | ECM | Refer to ELECTRONIC CIRCUIT INSPECTION PROCEDURE |
| Poor acceleration | ECM | Refer to ELECTRONIC CIRCUIT INSPECTION PROCEDURE |
| Engine stalls when starting off or stopping | ECM | Refer to ELECTRONIC CIRCUIT INSPECTION PROCEDURE |
| Malfunction in shifting | Park/Neutral position switch circuit* | Refer to DTC P0705: Transmission Range Sensor Circuit Malfunction (PRNDL Input) |
| ECM | Refer to ELECTRONIC CIRCUIT INSPECTION PROCEDURE |
HINT:
*: When the circuit is defective, a DTC may be stored.
CHAPTER 2: ON-VEHICLE REPAIR AND OFF-VEHICLE REPAIR
| Symptom | Suspected Area | See |
|---|---|---|
| Vehicle does not move in any forward positions or in R position | Manual valve | Refer to COMPONENTS |
| Primary regulator valve | Refer to COMPONENTS | |
| Front and rear planetary gear | Refer to COMPONENTS | |
| U/D planetary gear | Refer to COMPONENTS | |
| F2 U/D one-way clutch | Refer to COMPONENTS | |
| C1 forward clutch | Refer to COMPONENTS | |
| B3 U/D brake | Refer to COMPONENTS | |
| Vehicle does not move in R position | Front and rear planetary gear | Refer to COMPONENTS |
| U/D planetary gear | Refer to COMPONENTS | |
| C2 direct clutch | Refer to COMPONENTS | |
| C3 U/D brake | Refer to COMPONENTS | |
| B2 1st and reverse brake | Refer to COMPONENTS | |
| No up-shift (From 1st to 2nd) | Valve body assembly | Refer to COMPONENTS |
| F1 No. 1 one-way clutch | Refer to COMPONENTS | |
| B1 2nd brake | Refer to COMPONENTS | |
| No up-shift (From 2nd to 3rd) | Valve body assembly | Refer to COMPONENTS |
| C2 direct clutch | Refer to COMPONENTS | |
| No up-shift (From 3rd to 4th) | 3-4 shift valve | Refer to COMPONENTS |
| C3 U/D clutch | Refer to COMPONENTS | |
| No down-shift (From 4th to 3rd) | 3-4 shift valve | Refer to COMPONENTS |
| No down-shift (From 3rd to 2nd) | Valve body assembly | Refer to COMPONENTS |
| No down-shift (From 2nd to 1st) | Valve body assembly | Refer to COMPONENTS |
| No lock-up or no lock-up off | Lock-up relay valve | Refer to COMPONENTS |
| Torque converter clutch | Refer to INSPECTION | |
| Harsh engagement (From N to D) | C1 accumulator | Refer to COMPONENTS |
| Valve body assembly | Refer to COMPONENTS | |
| C1 forward clutch | Refer to COMPONENTS | |
| F2 U/D one-way clutch | Refer to COMPONENTS | |
| F1 No. 1 one-way clutch | Refer to COMPONENTS | |
| Harsh engagement (From N to R) | Valve body assembly | Refer to COMPONENTS |
| C2 direct clutch | Refer to COMPONENTS | |
| B2 1st and reverse brake | Refer to COMPONENTS | |
| Harsh engagement (Lock-up) | Lock-up relay valve | Refer to COMPONENTS |
| Torque converter clutch | Refer to INSPECTION | |
| Harsh engagement (From 2nd to 3rd) | Valve body assembly | Refer to COMPONENTS |
| Harsh engagement (From 3rd to 4th) | Valve body assembly | Refer to COMPONENTS |
| Harsh engagement (From 4th to 3rd) | Valve body assembly | Refer to COMPONENTS |
| Slip or shudder (forward position, after warm-up) | Oil strainer | Refer to COMPONENTS |
| Torque converter clutch | Refer to INSPECTION | |
| C1 forward clutch | Refer to COMPONENTS | |
| C2 direct clutch | Refer to COMPONENTS | |
| C3 U/D brake | Refer to COMPONENTS | |
| F1 No. 1 one-way clutch | Refer to COMPONENTS | |
| F2 U/D one-way clutch | Refer to COMPONENTS | |
| Slip or shudder (shift lever in R) | Oil strainer | Refer to COMPONENTS |
| C2 direct clutch | Refer to COMPONENTS | |
| B2 1st and reverse brake | Refer to COMPONENTS | |
| Slip or shudder (1st) | F1 No. 1 one-way clutch | Refer to COMPONENTS |
| Slip or shudder (2nd) | F2 U/D one-way clutch | Refer to COMPONENTS |
| B1 2nd brake | Refer to COMPONENTS | |
| Slip or shudder (3rd) | C2 direct clutch | Refer to COMPONENTS |
| Slip or shudder (4th) | C3 U/D clutch | Refer to COMPONENTS |
| No engine braking (1st to 3rd: D position) | B3 U/D brake | Refer to COMPONENTS |
| No engine braking (1st: L (1) position) | B2 1st and reverse brake | Refer to COMPONENTS |
| No engine braking (2nd: 2 position) | B1 2nd brake | Refer to COMPONENTS |
| Poor acceleration (all positions) | Torque converter clutch | Refer to INSPECTION |
| U/D planetary gear | Refer to COMPONENTS | |
| Poor acceleration (4th) | C3 U/D clutch | Refer to COMPONENTS |
| U/D planetary gear | Refer to COMPONENTS | |
| Large shift shock or engine stalls when starting off or stopping | Torque converter clutch | Refer to INSPECTION |
| No kick-down | Valve body assembly | Refer to COMPONENTS |
Factory Service Tools
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
Disclosure: Verified tool recommendations may earn an affiliate commission at no cost to you.
When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.