Home ReviewsRefund Car not listed?
Home/Oldsmobile/Eighty-Eight/Oldsmobile Eighty-Eight X (1996-1999)/Repair manual/Automatic Trans/Automatic Transaxle Diagnosis - 4T60-E: Other
Contents Wiring diagrams Section: Automatic Trans All sections

Automatic Transaxle Diagnosis - 4T60-E: Other Oldsmobile Eighty-Eight X

Automatic Trans ~1322 words

PCM

On "W" body models, PCM is located at right side of engine compartment. On all other models, PCM is located under right kick panel. PCM controls ignition, fuel and emission devices related to engine and transaxle upshifts and downshifts.

PCM receives electronic signals from sensors and switches. These signals help PCM determine when to operate various relays and solenoids related to engine and transaxle control.

SENSORS & SWITCHES

PCM controls upshifts and downshifts based on coolant temperature (or transaxle temperature), throttle position, transaxle range switch position, vehicle speed sensor and brake pedal switch. System also includes several other switches and sensors which are used for engine control. These components are covered in ENGINE PERFORMANCE.

SOLENOIDS

Transaxle is shifted up or down by 2 electric solenoids. Both solenoids are located on valve body. Ignition power is supplied to each solenoid by fused circuit. See WIRING DIAGRAMS .

Solenoid "A" controls hydraulic pressure to 1-2 and 3-4 shift valves. Solenoid "B" controls hydraulic pressure to 3-2 and 4-3 shift valves.

RETRIEVING CODES

Note. Stored DTCs may be retrieved from PCM memory using a factory recommended Tech 1 scan tool or aftermarket scan tool. DTCs CANNOT be retrieved by grounding 16-pin Data Link Connector (DLC). Plugging scan tool into DLC, located under instrument panel, enables user to read DTCs and check voltages in system on serial data line.

Scan tools may also furnish information on status of output devices (solenoids and relays). However, status parameters are only an indication that output signals have been sent to devices by control module; they do not indicate if devices have responded properly to signal. Check for proper response at output device using a voltmeter or test light.

If trouble codes are not present, this is not necessarily an indication a problem does not exist. Driveability related problems with codes displayed occur about 20 percent of the time, while driveability problems without codes occur about 80 percent of the time. Sensors that are out of specification WILL NOT set a trouble code but WILL cause driveability problems. Using scan tool is the easiest method of checking sensor specifications and other data parameters. Scan tool is also useful in finding intermittent wiring problems by wiggling wiring harness and connections (key on, engine off) while observing scan tool.

2.4L

  1. Turn ignition on, with engine off. Observe Malfunction Indicator Light (MIL). If MIL lights, go to next step. If MIL does not light, see A-1, MIL INOPERATIVE in «BASIC TESTING - 2.4L»(ref-20287) article in ENGINE PERFORMANCE.
  2. Turn ignition off. Install scan tool and follow scan tool manufacturer's instructions to proceed with test. Turn ignition on. If scan tool displays PCM data, go to next step. If scan tool does not display PCM data, see A-4, NO SCAN TOOL DATA in «BASIC TESTING - 2.4L»(ref-20287) article.
  3. Using scan tool, command MIL off. If MIL remains on, see A-2, MIL INOPERATIVE in «BASIC TESTING - 2.4L»(ref-20287) article. If MIL is off, using scan tool, check for any DTCs stored in current, history or MIL request. If any DTC is stored, go to next step. If no DTCs are stored, go to step 5.
  4. Using scan tool, save freeze frame and failure record information using "Capture Info" feature. If any DTC is indicated as "LAST TST FAILED", diagnose DTC. If DTC is not stored, check related circuit or component(s). See «SYSTEM/COMPONENT TESTS - 2.4L»(ref-20357) article.
  5. Attempt to start engine. If engine starts and runs, go to next step. If engine does not start or starts and dies, see NO START DIAGNOSIS (A-3) in «BASIC TESTING - 2.4L»(ref-20287) article.
  6. Turn ignition on, with engine off. Using scan tool, follow scan tool manufacturer's instructions to proceed with test. Check coolant temperature sensor and throttle position sensor operation. Start engine. Allow engine to reach normal operating temperature. Check coolant temperature, oxygen and manifold absolute pressure sensors and idle air control valve values.
  7. Repair related circuit or component(s) as necessary. See «SYSTEM/COMPONENT TESTS - 2.4L»(ref-20357) article. If all components are okay, see «TESTS W/O CODES»(ref-20301) article.

3.1L & 3.4L

  1. Turn ignition on with engine off. Observe Malfunction Indicator Light (MIL). If MIL lights, go to next step. If MIL does not light, go to A-1, MIL INOPERATIVE in appropriate BASIC TESTING article.
  2. Turn ignition off. Install scan tool and follow scan tool manufacturer's instructions to proceed with test. Turn ignition on. If scan tool displays PCM data, go to next step. If scan tool does not display PCM data, go to A-2, NO SCAN TOOL DATA in appropriate BASIC TESTING article.
  3. Attempt to start engine. If engine starts and runs, go to next step. If engine does not start or starts and dies, go to NO START DIAGNOSIS (A-3) in appropriate BASIC TESTING article. Repair as necessary.
  4. Using scan tool, observe DTC status on LAST TST FAIL function. If any DTC is stored, save freeze frame and failure record information using scan tool "Capture Info" feature. If a DTC is indicated as last test failed, diagnose DTC. If DTC is not indicated, go to next step.
  5. Using scan tool, display DTC failure records. If a DTC failure record is stored, save freeze frame and failure record information using scan tool "Capture Info" feature. If a failure record is stored, diagnose DTC. If DTC(s) are not stored, check related circuit or component(s). See appropriate SYSTEM/COMPONENT TESTS article.

3.8L

  1. Turn ignition on with engine off. Observe Malfunction Indicator Light (MIL). If MIL lights, go to next step. If MIL does not light, go to A-1, MIL INOPERATIVE in appropriate BASIC TESTING article.
  2. Turn ignition off. Install scan tool and follow scan tool manufacturer's instructions to proceed with test. Turn ignition on. If scan tool displays PCM data, go to next step. If scan tool does not display PCM data, go to A-2, NO SCAN TOOL DATA in appropriate BASIC TESTING article.
  3. Attempt to start engine. If engine starts and runs, go to next step. If engine does not start or starts and dies, go to NO START DIAGNOSIS (A-3) in appropriate BASIC TESTING article.
  4. Using scan tool, observe DTC statuses; MIL REQUEST, FAIL THIS IGN, LAST TST FAIL and HISTORY. If any of these DTC status are present, refer to affected DTC to diagnose problem. If DTC(s) are not present, check related circuit or component(s). See appropriate SYSTEM/COMPONENT TESTS article.

Criteria No. 1

Throttle position sensor is 18-45 percent and constant by 5 percent. 1-2 shift is commanded. Vehicle speed is 5-45 MPH. When 2nd gear is commanded and within 2.5 seconds, engine RPM is more than 110 RPM from engine RPM of commanded 1st gear.

Criteria No. 2

Throttle position sensor is 18-45 percent and constant by 5 percent. 2-3 shift is commanded. Vehicle speed is 25-55 MPH. When 3rd gear is commanded and within 2.5 seconds, engine RPM is less than 150 RPM from engine RPM of commanded 2nd gear.

Criteria No. 3

Throttle position sensor is 18-45 percent and constant by 3 percent. 3-4 shift is commanded. Vehicle speed is 35-80 MPH. When 4th gear is commanded and within 2.5 seconds, engine RPM is more than 5 RPM from engine RPM of commanded 3rd gear.

Criteria No. 4

Throttle position sensor is 7-37 percent. 4th gear is commanded and TCC is on. Speed ratio is between 40-42. TCC slip is 500-1000 RPM for more than 4 seconds.

Criteria No. 5

Throttle position sensor is 7-37 percent. 4th gear is commanded and TCC is on. Speed ratio is between 28-30. TCC slip is between -20 RPM and 25 RPM for more than 4 seconds.

Throttle position sensor is more than 37 percent. PCM is commanding 1st gear and speed ratio is less than 105 for 2.5 seconds. (shift valve stuck in off position).

Throttle position sensor is more than 18 percent. PCM is commanding 4th gear and speed ratio is more than 100 for 2 seconds (shift valve stuck in on position).

More articles — Automatic Transaxle Diagnosis - 4T60-E