P1870, TRANSAXLE COMPONENT SLIPPING Circuit Description PCM monitors Torque Converter Clutch (TCC) slip speed by calculating difference between engine speed and transaxle output speed. In D3 drive range with TCC engaged, engine speed should closely match transaxle output speed. DTC P1810 detects excessive TCC slip when TCC is engaged. Conditions For Setting DTC P1870 DTC will set under the following conditions: Ã DTCs P0122 and P0123 (throttle position), or P0502 (vehicle speed sensor) are not present. Ã Engine speed is 2000-3300 RPM. Ã MAP is 2.9-8.9 psi (20.3-61.5 kPa). Ã Throttle position angle is 13-35 percent. Ã TCC is on for 5 seconds or more. Ã TCC slip speed is 150-1000 RPM for 10 seconds. Ã Speed ratio is.98-1.34. Ã Vehicle speed is 40-65 MPH. Ã All conditions are met for 3 TCC cycles. DTC P1870 will be stored in PCM history. MIL will light at first failure signal and PCM will inhibit TCC engagement. Diagnostic Procedures 1. Ensure fluid level is correct. Inspect manual linkage for misadjustment or binding. Inspect throttle valve cable for misadjustment, binding or broken cable. Repair components as necessary, then go to step 9). 2. Check for low line pressure. See LINE PRESSURE TEST in 3T40 OVERHAUL article. If line pressure is within specification, go to step 6). If line pressure is not within specification, go to next step. 3. Check for restricted oil filter or missing or damaged filter seal. Check for missing pressure relief valve check ball. Check for damaged pressure relief valve or pressure regulator valve springs. Check pressure regulator valve for nicks or scored surface. Check for sticking pressure regulator valve. Check oil pump seals for wear or damage. Check for stuck oil pump slide, vane or drive pump damage. Repair components as necessary, then go to step 9). If components are okay, go to next step. 4. Connect scan tool to DLC. Turn ignition switch to ON position. DO NOT start engine. Using scan tool, record freeze frame and failure records for reference. Data will be lost when DTCs are NOTE: Perform OBD system check prior to performing diagnostic procedures. For wire terminal locations, see WIRING DIAGRAMS. For fluid circuit identification, see OIL CIRCUIT DIAGRAMS in section No. 1. Page 1 of 2 DIAGNOSIS - 3T40 -1996 Oldsmobile Achieva SC 8/24/2008
Checking wires and component.
COMPONENT & WIRING HARNESS RESISTANCE & VOLTAGE CHECK 1. Disconnect transaxle wiring harness connector. Turn ignition switch to ON position. Using a DVOM, measure voltage between ground and Pink wire terminal at engine side of transaxle wiring harness connector. Voltage should be 12 volts. If voltage is as specified, go to next step. If voltage is not as specified, repair fuse or wiring as necessary. 2. Turn ignition off. Using an ohmmeter, measure resistance at transaxle side of wiring harness connector between TCC solenoid terminal "A" (Pink wire) and 3rd gear pressure switch terminal "D" (Tan/Black wire). Resistance should be 19-31 ohms. 3. If resistance is as specified, go to next step. If resistance is not as specified, disconnect wiring harness at component and measure component resistance. Replace component if resistance is not as specified. If resistance is as specified, repair wiring harness between component and transaxle wiring harness connector. 4. Measure resistance between component terminals and ground. If resistance is low, replace component. If resistance is high, inspect wiring harness for short to ground. Repair as necessary. Page 1 of 1 DIAGNOSIS - 3T40 -1996 Oldsmobile Achieva SC 8/24/2008
Sunday, August 24th, 2008 AT 6:32 AM